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Biology 12 - ILO Summaries
Transcript of Biology 12 - ILO Summaries
- Involves designing experiments, testing a hypiothesis.
- Experiments are based on the testable prediction
- Must include: an independent variable, a dependent variable, one or more experimental groups, a control group, constant factors, and must be repeatable. What's Important?
- Water is called a polar molecule because each atom has a slight charge associated with it
- Structural formula of water: H - O - H What's Important?
pH - a measure of the hydrogen ion concentration of a solution; runs from 0 (acidic) to 14 (basic)
Acids - a substance that dissociates in water and increases the hydrogen ion concentration; are simply protons (proton donors); increasing the hydrogen ion concentration decreases the pH of a solution; pH of less than 7
Bases - a substance than dissociates in water and increases the hydroxide concentration; proton acceptors' they decrease the acidity [H+] of a solution, raising the pH of a solution; pH greater than 7
Buffering System - buffers are chemical combinations than maintain a normal pH; it prevents significant changes in pH and maintains homeostasis in our bodies; they are molecules than can either pick up or release H+ or OH- ions, resisting pH changes So What? The scientific method can be used to either prove or disprove a theory or hypothesis. As a learning tool, it can also further one's understanding of a concept or information. It can heighten understanding how and why things do what they do. 2 Covalent Bond Hydrogen Bond create a transport system, it acts as a cooling agent for humans and animals through vaporization of water/sweat, it moderates temperatures along the coasts, it prevents bodies of water to freeze bottom up, preserving life within the water habit as well as creating an insulator on the surface, most chemical reactions in life involve solutes dissolved in water, & much more. - Two covalent bonds (which are intramolecular - within the molecule) bind the two hydrogen atoms to the oxygen atom
- Weak hydrogen bonds are found between water molecules (intermolecular)
- Significant Properties: effective polar solvent, high heat capacity, high heat of vaporization, high surface tension/cohesion, & ice is less dense than liquid water So What? Water is one of the most important substances on Earth. Within it's many properties, water moderates temperature changes in the environment and in organisms, it allows water to fill a tubular vessel and So What? Acids are important in every day life, having a large impact on digesting our food, as well as assisting in tasks such as cleaning and disinfecting. Bases also play an important role in cleaning, and serve well in other ordinary tasks such as baking and brushing teeth (think baking soda!) Buffers are extremely important and critical in the blood of humans because any significant changes can lead to life threatening conditions. Buffers are 'built-in' the body, preventing changes in pH from occurring. Organic Molecules: What's Important? - Contains Hydrogen, Carbon, and Hydroxide
- Empirical Formula: CH O
- Can be in the form of:
Monosaccharides - consist of one sugar unit (simple sugars); the carbon atom can be arranged linearly or they may form a ring structure; three carbons - triose (i.g. glyceraldehyde), five carbons - pentose (i.g. ribose/deoxyribose), six carbons - hexose (i.g. glucose, fructose, galactose); most common is glucose, chemical formula - C H O ;
Disaccharides - when two sugars are linked together through dehydration synthesis; macromolecules; ex: maltose (2 glucose, 1 fructose), sucrose (1 glucose, 1 fructose), lactose (1 glucose, 1 galactose)
Polysaccharides - formed when many polymers are linked together through dehydration synthesis; macromolecules; most common are starch, glycogen, and cellulose 2 6 12 6 So What?
Carbohydrates are essential to living things and they are key energy source. Their function is mainly for quick fuel and short-term energy storage in organisms. Monosaccharides (i.e. glucose) and disaccharides (sucrose, lactose, maltose) are simple carbohydrates, while polysaccharides (starch, glycogen, cellulose) are more complex carbohydrates. Carbohydrates! Organic Molecules: Lipids!
- Three basic types:
a. neutral fats (triglycerides)
> 1 glycerol molecule & 3 fatty acid molecules through 3 dehydration synthesis reactions
> form either unsaturated fatty acids (double bonds between some carbon atoms, typically found from plant sources, liquid, 'kinky') or saturated fatty acids (many hydrogen atoms, no double bonds, typically found in animal fats, solid)
> two fatty acids, one glycerol, and a phosphate group (which, in turn, is linked to a nitrogen containing group), through dehydration synthesis
> phosphate end is polar, fatty acid tails are nonpolar; form a phospholipid bilayer when placed in water
> arranged in cell membrane & are the major components of the cell membrane structure
> wide range of functions: cholesterol used in cell membrane stabilization, sex hormones, non-sex hormones (ie. cortisol, recovery from stress and reduce
inflammation) many functions include energy storage, hormone production, cell membrane structure, insulation, etc. In referring to neutral fats, the nutrient properties vary - trans and saturated fats are the low end of the spectrum with the polyunsaturated fats on the other end. The structure of fats equal their functions and determine either the So what?
Lipids are essential to life and, without them, our bodies wouldn't be able to function. They are an excellence source of energy, energy being one of their key functions. The benefits they have or the harm effects they have. What's Important?
- composed of C, H, and O (may also contain small amounts of nitrogen and phosphorous)
- insoluble in water, non polar (exception - phospholipids) Organic Molecules: Proteins! What's Important?
- contain C, H, large amounts of O & N, and small amounts of S
- built from monomers/amino acids - therefore are polymers
- Wide variety of functions: catalyze specific enzymes, transport system, structural component, hormones, receptors, defense against pathogens, energy, allow organisms to move, etc.
- 20 different amino acids with can be linked together (through special covalent bonds called peptide bonds - through dehydration synthesis) to produce different proteins
- Amino Acids ~ contain C, H, N, O and sometimes S; the R-group is unique in each aa and determines the identity and function
- When 2 aa join together through dehydration synthesis, a dipeptide is formed. When many aa join together, a polypeptide is formed. Some proteins consists on only one polypeptide, while others consists of many polypeptides linked together. So what?
Protein is the building block for the human body; it is a vital part of every cell, tissue, and organ and is constantly being broken down and replaced. There is often the misconception that proteins are the greatest source for energy, however lipids and carbohydrates are much more resourceful in this. Proteins, however are still vital for the body to function properly, carrying an array of functions. Levels of Protein Structure:
a. Primary - determined by the linear sequence of aa, is stabilized by its peptide bonds
b. Secondary - the polypeptide arranged itself in a particular pattern, include alpha helix and the beta pleated sheet structures, is stabilized by hydrogen bonds
c. Tertiary - folding upon itself to form a globular structure, stabilized by hydrogen, ionic, and covalent bonds and hydrophobic interactions between the R groups of the aa
d. Quaternary - more than one polypeptide coming together to form the final globular protein, stabilized by hydrogen bonds and hydrophobic interactions
** A protein's FUNCTION is determined by its STRUCTURE Proteins have a large variety of structures/shapes with determine what that specific protein molecule will do in the body. Proteins can be found in animal based foods as well as plant based foods. Nucleic Acids Organic Molecules What's Important?
- composed of C, H, O, N, P
- the two types of nucleic acids are: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)
- polymers; consist of repeating subunits/monomers
- control cell activities and determine the traits possessed by organisms by controlling the process of protein synthesis
- To form a nucleotide, the elements are linked together through dehydration synthesis
- To form a strand, the nucleotides are linked through their sugar and phosphate groups though dehydration synthesis, creating phosphodiester bonds resulting in a sugar-phosphate backbone
- contains the genetic code which determines the structure and function of proteins
- consist of 2 strands of nucleotide monomers, twisted to form a double helix
- DNA nucleotides consist of: phosphate group, pentose sugar (deoxyribose), and nitrogenous bases (Adenine, Thymine, Guanine, and Cytosine --> A and G are called purines & consist of two rings, T and C are called pyrimadines and consist of one ring.) RNA
- is involved in taking the DNA genetic information and using it to link amino acids together in order to make proteins
- consist of one strand (single stranded) of nucleotide monomers
- nucleotides consist of: phosphate group, pentose sugar (ribose), and nitrogenous base (Adenine, Uracil, Guanine, and Cytosine)
- comes in three forms: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA) So what?
DNA makes up who we are and is the foundation of life. Nucleic acids are essential in all organisms as they carry essential genetic information which codes for protein synthesis which results in the structure and function, vital to life. RNA is important because it assists the process of using DNA information in producing a protein. DNA DNA What's Important?
- DNA replication ensures that a complete set of genetic instructions is passed on to the next generation of cells allowing them to manufacture all the proteins they require So What?
DNA replication is a preliminary step for cell division (both mitosis and meiosis) and is a necessary step before a cell divides. DNA must also be replicated to manufacture proteins. The leading strand in the process comes with no difficulties, however the lagging strand needs the extra help from the RNA primer, DNA polymerase enzymes, and DNA ligase as it runs 3' to 5', opposite to the leading strand. Since DNA replication results in each new double helix containing a parent and a daughter, it gets it's name "semi-conservative replication."
1. in the nucleus, the enzyme helicase unwinds and unzips the DNA double helix by breaking hydrogen bonds between the bases, creating a replication fork 2. both parental strands serve as templates in producing daughter DNA strands
3. the formation of new DNA is carried out mostly by the enzyme DNA polymerase and series of proteins.
4. a) on the leading stand, free nucleotides are used to construct a new DNA strand with complementary pairs joined with exposed bases
b) on the lagging strand, fragments of single-stranded DNA are created (Okazaki fragments). DNA ligase then comes in and joins neighboring fragments together into longer strands with phosphodiester bonds.
4. Results in 2 identical DNA double helices, each having on daughter strand and one parent strand. This is semi-conservative replication. Recombinant Replication! DNA Technology ! What's Important?
- This technology allows scientists to use enzymes to cut a gene from a chromosome of a particular organism (i.e. a human) and splice it onto the DNA of another organism (i.e. bacterium).
- This creates recombinant DNA which can then...
be taken up by a bacterial cell
which then makes a protein coded for by the gene
the bacteria is then cultured resulting in millions of daughter cells = millions of copies of the original gene (gene has been cloned). So What?
Recombinant DNA technology is important and results in many benefiting factors, however it also comes with negativity. A few of the ways it can benefit us as humans are: growth & differentiation regulators, improved diagnostic technology, enrichment of staple foods, detection of infectious agents in food, vaccines and medications, etc. Also, because of makeup of recombinant DNA technology, it allows large amounts of proteins to be produced relatively inexpensively. However, this technology also leads to harmful advances such as genetically modified foods, virus antibiotic resistance, among others. - Steps in Cloning
1. Plasmid is removed from bacteria
2. Restriction endonuclease cleaves open plasmid creating sticky ends
3. Desired gene is cut out of its chromosome with the same restriction endonuclease.
The sticky ends on both the plasmid and gene are complementary.
4. The cleaved plasmid is mixed with desired gene and with the enzyme DNA ligase, the two are spliced together creating a recombinate DNA plasmid 5. The recombinate DNA plasmid is added to the bacterial cell
6. The bacteria is cultured, producing many daughter cells, therefore many copies of the desired gene.
7. The many copies of the gene will be able to produce the protein coded from by that gene, totaling in a very high desired protein production. Protein Synthesis! What's Important?
- DNA genetic information determines the sequence of amino acids in protein synthesis
- the specific sequence in amino acids in the protein determines the structure and function (as result of the DNA)
- this also determines then the characteristics and activities of the cell
- RNA assists DNA in protein synthesis
- RNA comes in the following 3 forms: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA) - Two main stages of protein synthesis are:
molecules involved: RNA nuceotides, RNA polymerase, DNA template
Control - start and stop: promoter, release factor
molecules involved: mRNA, tRNA, amino acids, ribosomes, codons, release factor, energy
Control - start and stop: ribosomal package
product: polypeptide chains/protein So what?
Proteins are essential to life and organisms, and without them, survival wouldn't be possible. Proteins perform a huge variety of tasks, especially as a vital component in cells. Protein synthesis is important to produce the necessary proteins. Not only that, by the process of protein synthesis is important, as one error in the genetic information or amino acid sequence could cause significant changes in the protein structure, which alters its function. Gene Mutations how it affects protein synthesis What's Important?
- Gene mutations are changes in the sequence of the nitrogenous bases in DNA
- Are caused by environmental factors called mutagens
- Mutagens examples: radiation, some pesticides, industrial chemicals, chemicals in cigarette smoke, some food preservation chemicals
- Mutations alter the structure of the protein that the gene codes for and thus results in a loss or change of the protein's function
- A change in the nitrogenous bases in the DNA can change one or more of the amino acids used to make a protein and this could cause the entire structure and function to be altered
- Lost or altered protein function can result in genetic disease (i.e. sickle cell anemia, pheylketonuria) So What?
Gene mutations, while not all harmful, cause genetic variations and changes within an organism. Most mutations often are harmful, causing severe damage and many life threatening genetic diseases. The Cell Membrane! What's Important? 1. Channel Proteins - form passages allowing particles (H20, Cl-) to pass through
2. Specific Carrier Proteins - transfer So What?
The plasma membrane of a cell is vital to a cell's survival. It's main overall functions are to define boundaries, provide protection, and regulate what enters and leaves the cell. Each component and molecule are important for the structure and they each serve a crucial function. - cell membranes consists of...
* phospholipids (make up membrane's shape and barrier as well as fluidity)
* proteins (functions stated below)
* glycolipids and glycoproteins (have sugar chains attached to them; serve in cell recognition)
* cholesterol ( helps to prevent solidifcation at low temps. and fluidity at high temps.)
- cell membrane >>> fluid mosaic model
*said to be fluid because of the phospholipid fluidity and mosaic because of the pattern the embedded proteins create
- The Proteins
* either integral proteins or peripheral proteins
- integral have specific functions. - the cell membrane defines the boundaries of the cell and holds the cytoplasm/contents inside the cell
- it provides protection for structures found inside the cell
- membranes regulate what enters and leaves the cell (permeability)
- based on size alone >> semi permeable
- based on chemical and physical properties >> selectively permeable
- cell membranes regulate based on chemical, physical properties, and size >> therefore selectively permeable 3. Specfic Receptor Proteins - allow specific molecules (hormones) to bind to the proteins and affect cellular metabolism
4. Cell Regonition Glycoproteins - bound to short chains of sugars and are part of the major histocompatibility which identifies the cell
5. Enzymatic Proteins - catalyze specific reactions specific particles (Na+, K+) across Passive Transport Active Transport Diffusion - molecules of liquids, dissolved solids, and gases are able to move into or out of a cell. They follow a concentration gradient; toward lower concentration
Osmosis - movement of water through a semipermeable membrane into a solution of higher solute concentration (concentration gradient)
Facilitated Transport - diffusion involving a carrier system and concentration gradient; the passage of molecules across the membrane even though they are not lipid-soluble; toward lower concentration no energy used energy used molecules involved molecules involved lipid-soluble molecules, water, gasses (ex. N, O, H2O, CO2) water some sugars (ex. glucose), amino acids, sodium ions, chloride ions Exocytosis - vesicles budded off the Golgi apparatus or E.R. can fuse with the plasma membrane, secreting their contents
Pinocytosis - ingestion of a fluid or a suspension into the cell. The plasma membrane encloses some of the fluid and pinches off to form a vesicle
Phagocytosis - ingestion of solids from outside the cell. The plasma membrane encloses a particle and buds off to form a vacuole. Lysosomes fuse with it and digest contents
Active Transport - molecules/ions pass through membrane toward higher concentration by use of carrier and energy against concentration gradient. macromolecules, hormones (ex. insulin), digestive enzymes, antigens macromolecules, fluids solids (food or bacteria), viruses sugars, amino acids, ions (ex. iodine, glucose,
N+, K+, NaCl, Cl-) The Cell Membrane Cont'd passage of molecules factors affecting the rate of diffusion Temperature - the higher the temperature, the more kinetic energy, the faster the rate
Particle Size - larger the molecule, the slower the rate; the smaller the molecule, the faster the rate
Concentration Gradient - the greater the gap of concentration, the faster rate of diffusion
Density of the Medium - higher the density, the slower rate of diffusion example of phagocytosis The Cell Membrane Cont'd Solutions and their effects on cells Isotonic Solutions - the concentration of solute inside the cell is equal to that of outside the cell; therefore, there will be no net movement of water by osmosis, and have no effect on the cell.
Hypertonic Solutions - the concentration of solute outside the cell is greater than that of inside the cell; therefore, the net movement of water by osmosis will be from inside the cell to the outside. This will cause an animal cell to crenate (shrink) and a plant cell to to undergo plasmolysis, the tugor pressure decreasing.
Hypotonic Solutions - the concentration of solute outside the cell is less than that of inside the cell; therefore, the net movement of water by osmosis will be from outside the cell to the inside. This will cause an animal cell to swell and possibly lyse and a plant cell to to increase in tugor pressure. So What?
All of these process reply on the permeability of the plasma membrane as well as have a great impact on the cell alone. A cell could be physically altered having been placed in a hypotonic or hypertonic solution, which would affect its function or destroy the cell altogether. Enzymes! Metabolism:
- is the sum of all biochemical reactions which occur within an organism
- often arranged in pathways called metabolic pathways such as aerobic cellular respiration
* anabolic pathways - combine smaller molecules into large, require energy
* catabolic pathways - break larger molecules into smaller, energy is released
- each reaction is often catalyzed by a particular enzyme Enzymes: made of protein, increase rate of reactions in organisms, has an active site (with a specific structure to a specific substrate) where a substrate binds to, only catalyzes a specific reaction Substrate: the reactant of an enzyme catalyzed reaction which gets converted into the product Enzyme-Substrate Complex: the combination of the enzyme and the substrate bound to the enzyme's active site
1. kinetic energy cause enzymes and substrates to collide
2. in a successful collision, the substrates enter and bind to the enzyme's active site, forming the enzyme-substrate complex (held together by H bonds)
3. active site then changes shape slightly to hold the substrate in a process called induced fit
4. within the active site, the energy is lowered by creating an unstable transition state by placing stress on chemical bonds and arranging the substrates so that a reaction can easily occur between them
5. cofactors may assist the enzyme in catalyzing the reaction by accepting or contributing atoms
6. once the reaction is complete, the product is released from the enzyme's active site
7. enzyme then resumes its original structure and is ready to accept substrates once again Catalysts:
- substance that increases the rate of a chemical reaction without being permanently 'used up'
- increase the rate of chemical reations by lowering the activation energy
- Enzymes are catalysts that are made up of protein
- Each type of enzyme has a specific structure which only allows it to catalyze a specific reaction Steps in Enzyme Catalysis: Factors Affecting Enzyme Catalysis: Temperature - as temperature increases toward optimal temperature, there is more kinetic energy; therefore there will be an increased rate of successful collisions and formation of enzyme-substrate complexes; reaction rate will increase. If temperature increases above optimal temperature, the enzyme starts to denature and the active site changes shape; therefore decreased rate of successful collisions and formation of enzyme-substrate complexes; reaction rate decreases. pH - enzymes have a specific optimal pH varying on its location; as pH increases above or decreases below optimal pH, the enzyme starts to denature and the active site changes shape; therefore there is a decreased rate of successful collisions and formation of enzyme-substrate complexes; reaction rate decreases. Substrate Concentration - at very low substrate concentrations, reaction rate is very slow; as concentration increases, there will be an increased rate of successful collisions and formation of enzyme-substrate complexes; reaction rate will increase. Once it hits a certain level, however, all active sites are occupied and is saturated to the point were the reaction rate will not increase. Reaction rate can only increase at this point by adding more enzymes. Enzyme Concentration - at very low enzyme concentrations, reaction rate is slow. As concentration increases, there will be an increased rate of successful collisions and formation of enzyme-substrate complexes; reaction rate will increase. Competitive Inhibitors - are so similar to substrate in structure that they occupy active site; it competes with substrate; it prevents the substrate from occupying active site and prevents the reaction; therefore as the concentration of these inhibitors increases there will be a decreased rate of successful collisions and formation of enzyme-substrate complexes; reaction rate will decrease.
Noncompetitive: do not compete, however they bind to another site on the enzyme, causing the enzyme to change conformation; therefore the substrate will no longer fit into active site, decreasing the rate of successful collisions and formation of enzyme-substrate complexes; reaction rate decreases. Nucleus - surrounded by the nuclear envelope which consists of double membranes with pores which allow particles to pass between the nucleus and cytoplasm; inside consists of DNA and proteins; DNA controls the process of protein synthesis, DNA replication takes place in nucleus, the nucleoli are the sites where rRNA is produced which is then combined with proteins to form ribosomes Mitochondria - bean shaped organelles surrounded by an inner and outer membrane, the inner membrane is highly folded which produces cristae, proteins are embedded in crista, the compartment inside the inner membrane is called matrix which contains DNA and ribosomes; involved in aerobic cellular respiration (by making ATP); cell's powerhouse! Chloroplast - found only in plants, have inner and outer membranes, the fluid filled space in the inner membrane is called stroma, flattened sacs called thylakoids arranged in grana stacks are contained in the stroma, chorophyll is embedded in the thylakoid sacs, the stroma also contains DNA and ribosomes; are the site for photosynthesis (solar energy is trapped chlorophyll and used to produce sugars >> converted to chemical energy, reactant molecules are CO2 and H2O, Oxygen is the byproduct Ribosomes - made up of large and small subunits, consist of protein and rRNA, may be attached to the rough E.R. or float freely in cytoplasm; are used in protein synthesis (translation), from the rough E.R. they are transferred to the Golgi where they are packaged into vesicles Vacuoles and Vesicles - both membrane bound sac-like structures used for storage and support (in plants), vesicles are smaller than vacuoles; store materials such as water, nutrients, wastes, vesicles transport materials inside cell or secrete them outside of the cell Lysosomes - are vesicles formed by the Golgi apparatus, contain hydrolytic digestive enzymes; when macromolecules or pathogens enter the cell, lysosomal enzymes digest the particle (intracellular digestion), also digest worn out cell organelles or entire cells (auto digestion) Endoplasmic Reticulum - membranous channels and sacs that extends from the outer membrane of the nuclear envelope into the cytoplasm, rough E.R. has ribosomes on surface, smooth E.R. does not, rough and smooth E.R. are joined together; it transports molecules, rough involved in protein synthesis (translation), smooth E.R. detoxifies drugs, produces steroid hormones and phospholipids for membrane Golgi Apparatus - consists of (3 -20) sacs which are arranged in a stack with vesicles along edges, contain enzymes, inner face directed towards E.R. and outer face toward plasma membrane; receives vesicles containing lipids and proteins from E.R. which then chemically modifies and sorts them, repackaging them into vesicles, some secretory vesicles transport material outside of the cell, others contain hydrolytic enzymes for intracellular digestion Cytoskeleton - network of interconnected filamentous proteins (with actin filaments, microtubles, and intermediate filaments), is suspended in cytoplasm, gives gel-like consistency; provides attachment site for cell's shape and maintains shape, allows cell to change shape and move Plasma membrane and cell wall - membrane defines the boundaries of the cell and holds the cytoplasm inside the cell, provides support and protection for structures inside as well as regulates what enters and leaves the cell. // the cell wall is only in plants and is a tough, rigid layer on the outermost surface, providing even more structure and protection to the cell Cytoplasm - the gel-like substance that fills the cell, suspends the cytoskelton and provides shape, movement, and support for organelles; all of the cell's contents and contained in the cytoplasm Cells' Structures and Functions! Limits to Cell Size! There are almost no cells with a diameter larger than 300 micrometers. What's Important?
As cells increase in size, their surface area increases at a slower rate than their volume (ex: 1 micrometer: SA - 1x1 = 1 um x 6 = 6 um , volume - lwh = 1um , ratio - 6/1 or 6)
As cells increase in size, their SA to V ration decreases, meaning there is less SA per unit of volume.
Once a cell reaches a certain size, they divide to prevent growing too big, which then increases their SA/V ratio again. So What?
Through the cell's surface (membrane), nutrients and wastes are exchanged which is necessary to keep the cell alive. In order to stay alive, the cell must have a fairly large amount of SA for each unit of volume in order to bring in enough nutrients and remove enough wastes.
Thus, a cell must have a relatively large SA/V ratio, causing all cells to be very small in size. Digestive System! MouthStructure: is bounded externally by the lips and cheeks Function: Receives food and is the location where food enters the digestive system. Mechanical and chemical digestion both occur here for the first time TongueStructure: Inside the month; composed of skeletal muscle that contracts to change the shape of the tongueFunction: Forms the bolus Salivary Glands
Structure: Glands (a structure like a pocket or sleeve) that lie in various areas of the mouth: either side of the face immediately below and in front of the ears, beneath the tongue, beneath the flood of the mouth.
Function: Secrete salivary amylase which begins process of chemical digestion So What? These four structures contribute to chemical and mechanical digestion which are both processes which break down food into moderate sized pieces for swallowing so that further digestion can take place in the body. PharynxStructure: muscular passageway connecting oral cavity with esophagus Function: Forces food into the esophagus after leaving the mouth in the process of swallowing. EsophagusStructure: muscular tube with walls that contain two layers of smooth muscleFunction: conducts food from the pharynx to the stomach by pushing the food due to rhythmic waves of contraction Cardiac SphincterStructure: a ring-like muscle at the junction of the esophagus and stomachFunction: prevents back flow from the stomach by contracting and closing off the entrance to the stomach So what? The pharynx, epiglottis, esophagus, and cardiac sphincter are all involved in the important action of swallowing food. When food is swallowed, it passes through the pharynx (which a soft palate closes off) and the glottis (which the epiglottis covers), forcing the bolus down the esophagus which pushes it past the cardiac sphincter and into the stomach where further digestion will take place. StomachStructure: J-shaped, expandable sac which lies in the abdominal cavity just beneath the diaphragm; the walls have 3 layers of smooth muscle and have rugae (large folds) in the walls. Function: Receives the swallowed bolus and mixes the food with gastric juices secreted from glands in the walls. The rugae allow the stomach to expand in order to hold a large volume. The mixing of the bolus with gastric juices forms a substance called chyme. Pyloric SphincterStructure: tough ring of smooth muscleFunction: acts like a valve, repeatedly opening and closing, which controls the flow of acid chyme from the stomach into the small intestine. Small IntestineStructure: has a small diameter, but is an average of 6 meters in length; tubular-like structureFunction: Receives the acid chyme and chemical digestions occurs here as well as absorption of nutrients. After the tract, it releases the remaining substance into the large intestine. DuodenumStructure: The first, shortest, and widest portion of the small intestineFunction: receives bile which is secreted from the liver and gall bladder and pancreas. Gall bladderStructure: a pear-shaped muscular sac attached to the surface of the liverFunction: Excess bile produced from the liver in stored here. When needed, bile leaves the gall bladder and proceeds to the duodenum. AppendixStructure: Sits at the junction of the small intestine and large intestine, attached to cecum; thin tube about four inches longFunction: Rather useless. Large Intestine (Colon)Structure: Large in diameter and short in length. Function: Receives substance from small intestine and absorbs water, salts, and some vitamins. Also storms indigestible material until it is eliminated as feces. RectumStructure: The last 20 cm of the large intestineFunction: Opens at the anus, passing whats left of the 'food' along AnusStructure: Opening at the end of the digestive tractFunction: Eliminates feces by the contraction of its walls. End of digestive system. So What? The Intestinal Tract is essential in the continuation of chemical and mechanical digestion. Between the small intestine and the anus, all of the nutrients, vitamins, and water are absorbed into the blood stream and the 'leftovers' (feces) are eliminated from the body since they are made up of indigestible material and bacteria. TeethStructure: Various shapes (i.e. the chisel-shaped incisors, the pointed canine, the flat molars)Function: Bite, tear, and grind food; chewing the food (mechanical digestion) Epiglottis Structure: a flap of tissueFunction: covers the glottis, preventing food from entering the respiratory system LiverStructure: Largest gland in the body, lies in the upper right section of the abdominal cavity, under the diaphragmFunction: Removes and stores iron and certain vitamins. Produces bile from cholesterol and they emulsify fat into the small intestine. PancreasStructure: An elongated and somewhat flattened organ, deep in the abdominal cavity. Function: Secretes insulin and glucagon which are hormones that keep the blood glucose levels within normal limits. Also produces pancreatic juice, which contains sodium bicarbonate to help neutralize the stomach acid, and digestive enzymes for all types of food. Digestive System Cont'd So What?
The Digestive Enzymes are important in digestion as they are one of the key features in chemical digestion. Different types of food and substances correspond with a specific enzyme which is used to break down the particle into molecular sized so that it can be absorbed into the blood. Juices in the digestive system are also important in the role of chemical digestion. They also help break down the food in the location of the juices. The importance of the pH levels in the digestive system, is that affect how well food will be digested. A few considering factors regarding pH is that if a specific region is not the optimal pH for an enzyme, the enzyme could denature and therefore not break down the food. Therefore pH keeps various regions functioning properly and effectively while pH can also kill bacteria that enters the digestive tract (i.e. in the stomach). Role of Water: It is an important factor the production of digestive juices, saliva, and bile. Water is a solute for these materials and, especially in the stomach, it aids the function of the releasing of gastric juices for break down of food. Sodium Bicarbonate in Pancreatic Juices: Neutralizes the acidic material from the stomach. Hydrochloric Acid in Gastric Juices: Creates a highly acidic environment in gastric cavity which activates the inactive form of the pepsin enzyme (Pepsinogen) which is essential in the stomach for chemical digestion Mucus in Gastric Juices: provides a physical barrier to prevent gastric acid from damaging the stomach walls The Heart! structure and function Veins: 3 layers of walls with thinner smooth muscle and elastic fibers, with one way valves to prevent back flow of blood; carry low pressure blood to the heart
Pulmonary veins: carry oxygenated blood to the heart from the lungs.
Systemic veins (superior & inferior vena cava): carry deoxygenated blood to the heart from the body. Atria: relatively thin cardiac muscular chambers, only moving blood into the ventricle from the veins
Right: receives blood from Superior & Inferior Vena Cava and pumps it into the Right Ventricle through Tricuspid Valve
Left: receives blood from Pulmonary Veins and pumps it into the left ventricle through bicuspid valve Atrioventricular valves: between the aria and ventricles, prevent back flow of blood when ventricles contract, are anchored to the walls by chordae tendineae (fibers that prevent the flaps from inverting)
Tricuspid: has three flaps, between right atrium and ventricle
Bicuspid: has two flaps, between left atrium and ventricle Ventricles: thicker cardiac muscular chambers, pumping blood through pulmonary and systemic systems
Left: thickest walls since has to pump blood through entire body (systemic)
Right: not as thick since only has to pump blood to lungs (pulmonary) Semi-lunar Valves: 'half moon' shaped valves, they allow blood to be forced from the ventricles into the exists of the heart
Pulmonary Semi-lunar: on right side, between right ventricle and pulmonary trunk; prevents back flow of blood
Aortic Semi-lunar: on left side, between left ventricle and aorta; prevents back flow of blood Pulmonary Trunk: blood vessel that divides into the two pulmonary arteries that carry deoxygenated blood pumped from the right ventricles of the heart to the lungs Aorta: blood vessel that divides into several different arteries that are part of the systemic circulatory system, caring oxygenated blood from the heart into the cells and tissues of the entire body. Arteries: three layers of tissue muscle and elastic fibers with a cavity (lumen) which carries blood away from the heart.
Pulmonary arteries: carry deoxygenated blood from pulmonary trunk to the lungs
Systemic arteries: carry oxygenated blood from aorta into different cells/tissues of the body Coronary Blood Vessels: embedded in the heart's muscular walls which include: arteries, capillaries, venules, and veins; supply heart tissue with O2 and nutrients and remove CO2 and wastes; part of systemic system Septum: muscular wall that divides the heart into right and left sides, preventing deoxygenated blood from the right side mixing with oxygenated blood from the left side So what? The heart acts as the circulatory system's pump and, as a result of it's muscular walls, blood is pumped through blood vessels which bring blood to all the body's cells/tissues. The heart is responsible for pumping blood through both circulatory systems: pulmonary (associated with lungs) and systemic (rest of the body) Sinoatrial (SA) node: in the dorsal wall of the right atrium; initiates the heartbeat due to the impulse it emits Atrioventricular (AV) node: in the ventricle wall of the right atrium; picks up impulse by SA node and conducted downward through the septum by the Bundle of His Purkinje fibres: at the base of the septum; impulse is picked up and conducts it throughout the walls of both ventricles Autonomic nervous system
(effect on heart rate and blood pressure) Systolic
- systole: contraction period of the heart muscle/chamber during cardiac cycle
- systolic pressure: arterial blood pressure and ventricular blood pressure during the systolic phase of the cardiac cycle
Hypertension: prolonged and abnormally high blood pressure
contributing factors include: excessive saturated fat and cholesterol in the diet (artheroselerosis), excessive salt intake in the diet, nicotine from cigarette smoke, genetic factors, some disease such as diabetes and certain kidney diseases
Hypotension: prolonged and abnormally low blood pressure
contributing factors include: excessive blood loss, decreased cardiac output, leaky heart valves The Heart! Heartbeat, heart rate, blood pressure This causes the ventricular systole which forces the blood out of the ventricles and into the pulmonary trunk and aorta; while the ventricles are undergoing systole, the atria are undergoing distole and filling with blood. High Blood Pressure (Hypertension)
is the stimulus that...
sends an impulse in medulla oblongata which...
travels along parasympathetic division and...
causes a decrease in heart rate,
a weaker heartbeat, and...
a decrease in blood pressure Low Blood Pressure (Hypotension)
is the stimulus that...
sends an impulse in medulla oblongata which...
travels along sympathetic division and...
causes an increase in heart rate,
a stronger heartbeat, and...
an increase in blood pressure Diastolic
- diastole: relaxation period of the heart muscle/chamber during cardiac cycle
- diastolic pressure: arterial blood pressure and ventricular blood pressure during the diastolic phase of the cardiac cycle
vs. The Difference Between....
Blood Vessels Arteries: carries blood away from the heart; thick, 3 layered walls and highly elastic which allows them to stretch in response to large changes in blood pressure; no valves
Arterioles: carry blood away from the heart between arteries and capillaries; mostly the same 3 layers as arteries, however can change their diameter by vasoconstriction and vasodilation; no valves
Capillaries: allows exchange of nutrients and wastes and gases (O2 and CO2) between tissues and blood through diffusion; one cell thick to allow small molecules to pass through, highly branched, form capillary beds which maximize surface area for exchange; no valves
Venules: carries blood towards the heart, conduct low pressure blood from capillaries to veins; 3 layered walls similar to arteries, but middle layer is not well developed therefore thinner; has valves
Veins: carry low pressure blood towards the heart; 3 layered walls with thinner middle layer, have large lumen; have one way valves to prevent back flow of blood Coronary arteries: behind flaps of semi-lunar valves, systemic, supply oxygenated blood to heart tissues
Coronary veins: in grove between left atrium and ventricle, systemic, return deoxygenated blood from heart to right atrium
Pulmonary trunk: coming off right ventricle, pulmonary, divides into pulmonary arteries
Pulmonary arteries: coming off pulmonary trunk, pulmonary, carries deoxygenated blood to lungs
Aorta: attached to left ventricle & top of the heart, systemic, path for blood to any organ in body
Subclavan arteries: extends from brachiocephalic artery to right side of the body and from aortic arch to left side, systemic, supplies oxygenated blood to arms and chest
Subclavan veins: under collar bone, systemic, drains blood from upper extremities into superior vena cava
Carotid arteries: neck from brachiocephalic trunk to right side and aortic arch in thoracic region, systemic, supplies oxygenated blood to head and neck
Jugular veins: attached to subclavan veins, systemic, drains deoxygenated blood from head into superior vena cave
Mesenteric arteries: arise from anterior surface of aorta, systemic, supplies oxygenated blood to intestines
Hepatic veins: from liver to inferior vena cava, systemic, drains deoxygenated blood from liver into heart
Hepatic Portal vein: between gastrointestinal tract, spleen, and liver, systemic, carries deoxygenated blood through these organs and connects with hepatic vien after blood is processed
Renal arteries: off abdominal aorta below superior mesenteric artery, systemic, supplies oxygenated blood to kidneys
Renal veins: connect kidney to inferior vena cava, systemic, drain deoxygenated, purified blood from kidneys
Iliac arteries: forms at terminus of aorta, systemic, supplies oxygenated blood to pelvic organs, legs, reproductive organs, etc
Iliac veins: drains into inferior vena cava from lower extremities, systemic, drains deoxygenated blood from pelvis and lower limbs into the heart
Superior Vena Cava: on the right side of heart (anterior), systemic, drains deoxygenated blood from upper extremities into right atrium
Inferior Vena Cava: on the right side of heart (posterior), systemic, drains deoxygenated blood from lower extremities into right atrium