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Human Skeleton & Bones
Transcript of Human Skeleton & Bones
Introduction to the Skeletal System
Components of the human endoskeleton:
Ligaments (connecting bone to bone)
Tendons (connecting bone to muscle)
Composed of 270 bones at birth, 206 in adults
230 moveable and non-moveable joints
27 bones in the hand
14 bones in the face
The shortest bone is the stirrup in the ear (1/10 of an inch!)
The longest bone is the femur (1/4 of the height)
Composed of 126 bones
Functionally involved in the locomotion (lower limbs) and the axial skeleton
The appendicular skeleton forms during development from cartlilage, by the process of endochondral ossification.
Type of Bone Cells & Bone Remodelling
Mature bone cells
Break down bone matrix for remodeling and release of calcium
Bone remodeling is a lifelong process by both osteoblasts and osteoclasts, bone tissue is replaced.
Cartilage is a flexible connective tissue found in many bones and serves as a hydraulic to them
Bones contain blood vessels, cartilage does not
It is not as hard as the bone, but it is harder than muscle
In adults, cartilage is found in the bridge of the nose, and in joints
The human embryo is primarily made of hyaline cartilage, but during development most of it is replaced by bone (ossification)
Skeletal Disease: Osteoporosis
Osteoporosis is a term that means "porous bones."
It is a skeletal disease affecting women and men.
Osteoporosis is a condition in which bones have lost minerals especially calcium, making them weaker, more brittle, and susceptible to fractures (broken bones).
The most common places where fractures occur are the back (spine), hips, and wrists.
Cancellous vs Cortical Bone
Less minerals and more collagen
Structure alike a honeycomb
Flexible, but not stress resistant
Can absorb shock due to the ability to change shape
One common location is the spine
What the Bone Is Made of
Bone consists of much smaller proportion of water than other body parts
2. Calcium carbonate (CaCO3) and calcium phosphate:
Bones Contain 99% of the body's calcium
These two compounds are 60-70% of bone weight
Provide the bone’s stiffness and resistance to pressing forces
3. Collagen (structural protein in animals.):
Gives bone flexibility and contributes to its ability to resist pulling and stretching forces
With aging, collagen is lost progressively and bone becomes more brittle (easily breakable).
Bone Classification According to Shape
Long- bones are longer than they are wide (arms, legs)
Short- usually square in shape, cube like (wrist, ankle)
Flat- flat , curved (skull, Sternum)
Irregular- odd shapes (vertebrae, pelvis)
Bones & Fitness
Regular physical activity and habitual loads make bones become denser and more mineralized
e.g. Right forearm of the right-handed tennis player is more dense than his left one from using it more frequently, the left foot of a left-footed football player is more dense than his right.
Inactivity works in the opposite direction, leading to a decrease in weight and strength.
e.g. Loss of bone mass has been noted in bed-ridden patients, inactive senior citizens, and astronauts
A joint or articulation (or articulate surface) is the location at which bones connect.
1. Fibrous (immovable)- solely connects bones, no movement (skull and pelvis)
2. Cartilaginous (slightly movable)- bones are attached by cartilage, little movement (ribs and spine)
3. Synovial (freely movable)- much more movement than cartilaginous joints. Cavities between bones are filled with synovial fluid which helps in the lubrication and protection of the bones (knee, shoulder)
Ligament is the fibrous tissue that connects bones to other bones and is also known as articular ligament, articular larua, fibrous ligament, or true ligament.
A tendon (or sinew) is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension.
Made up of collagen
A common tendon is the Achilles tendon
(structural support for the entire body)
Surrounding of soft tissue
(ex. the skull protects the brain)
(skeletal muscle is attached to bone so it pulls on the bone when it contracts)
(stores calcium and phosphorus, releasing minerals when needed)
of minerals and lipids
Blood cell production
(red bone marrow produces red and white blood cells.
The Main Division
The main division: axial and appendicular skeleton.
Axial skeleton: skull, vertebrae, ribs and sternum
Appendicular skeleton: limbs and girdles
The Six Regions
Pectoral girdles (4 bones) - Left and right clavicle (2) and scapula (2).
Arms and forearms (6 bones) - Left and right humerus (2) (arm), ulna (2) and radius (2) (forearm).
Hands (54 bones) - Left and right carpals (16) (wrist), metacarpals (10), proximal phalanges (10), intermediate phalanges (8) and distal phalanges (10).
Pelvis (2 bones) - Left and right hip bone (2).
Thighs and legs (8 bones) - Left and right femur (2) (thigh), patella (2) (knee), tibia (2) and fibula (2) (leg).
Feet and ankles (52 bones) - Left and right tarsals (14) (ankle), metatarsals (10), proximal phalanges (10), intermediate phalanges (8) and distal phalanges (10).
Through anatomical variation it is common for the skeleton to have many extra bones (sutural bones in the skull, cervical ribs, lumbar ribs and even extra lumbar vertebrae).
Unlike the axial skeleton, the appendicular skeleton is unfused. This allows for a much greater range of motion.
The skull consists of 28 different bones (including the ossicles of the ear)- cranium and facial bones
The vertebral column forms the central part of the skeleton. It supports the skull and protects the spinal cord. It also serves as attachment for the ribs, the pectoral and pelvic girdles.
The twelve pairs of ribs articulate with 12 vertebrae. The ribs are flat, narrow bones with a distinctive bow-shaped curve.
The sternum is a long, flat, dagger-shaped bone. It is about 15 - 18 cm long and is found in the center of the chest region.
Video for Revision
Cause & Diagnosis
Osteoporosis itself has no symptoms; its main consequence is the increased risk of bone fractures, swelling and pain
It is diagnosed with X-ray bone density machine, with a bone mineral density test or an ultrasound
1. Sex. Women are much more likely to develop osteoporosis than are men.
2. Age. The older you get, the greater your risk of osteoporosis.
3. Race. You're at greatest risk of osteoporosis if you're white or of Asian descent.
4. Family history. Having a parent or sibling with osteoporosis puts you at greater risk, especially if you also have a family history of hip fractures.
5. Frame size. Men and women who have small body frames tend to have a higher risk because they may have less bone mass to draw from as they age.
Details & Treatment
1. What are the two classifications of bones according to porosity?
2. What are the components of the skeletal system? Give a description of each of them.
3. Explain the process of bone remodeling.
4. What are the three types of bone cells and their purpose?
5. What are tendons made of?
6. Which bones make up the axial skeleton? (One can use Charles Skelington to demonstrate)
7. List at least 3 functions of the skeletal system.
8. What are the common causes and risk factors of osteoporosis?
9. How is osteoporosis treated?
THANK YOU FOR YOUR ATTENTION!
Feel free to ask any questions related to the topic and my presentation!
Based on Jim Harvey's speech structures
Classification according to the degree of porosity:
1. Cancellous bone aka spongy bone (high porosity)
2. Cortical bone aka compact bone (low porosity)
Less collagen and more minerals
Stiffer and stress resistant, but not flexible
Able to withstand stress where there is more load
One common location is the leg bone
The axial skeleton is the portion of the human skeleton that consists of the bones of the head and trunk of an organism.
Consists of 80 bones
Ossicles, skull, vertebral column, rib cage, hyoid bone
The balance between bone resorption and bone deposition is determined by the activities of two principle cell types, osteoclasts and osteoblasts
If the activity of osteoclasts increases, osteoporosis occurs
1. Healthy habits, an exercise plan and a healthy lifestyle.
2. Medications (bisphosphonates): alendronates, risedronates, ibandronate and zoledronic acid.
3. Avoiding a sedentary lifestyle, tobacco consumption (smoking) and alcohol.