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Plants become etiolated in the dark.

i.e. grow abnormally tall and thin and yellowish. The chloroplasts can't develop properly in the dark.

In the previous figure, auxins have collected in the shady part of the stem or shoot making the side grow faster and bending towards the light...

Liver cells convert glycogen into glucose

Blood sugar levels

Islets produce insulin

Auxins are made in the plant cells. But made in the tip of the plant and diffuse downwards to rest of growing shoot.

---->Light shinning onto a plant from the side, makes the opposite side grown faster and bend toward the light...

The use of hormones in animals we harvest. eg: bovine somatotrophin or BST. Leads to more milk production. You should read about the ramifications of using BST...i.e.: -Pro's and Con's

Hormone: a chemical substance produced by a gland, carried by the blood, which alters the activity of one or more specific target organs and is then destroyed by the liver.

Ethene gas (is an odd type of hormone-like substance)------------------->used to rippen fruit. As fruit is rippening they give off natural ethene gas. So if you want an avocado or guava to rippen faster, put them in a bag to trap the gas.

Situations in which adrenaline secretion increases

  • Sports: competitions, extreme sports...
  • Stressful situations: taking examinations, giving a public performance...

Position: one above each kidney.

The adrenal medulla (inner zone) produces adrenaline in responses to a stressful situation.

Adrenaline allows a quick response in dangerous situations when you have to run away or put up struggle:

  • Increases the pulse rate: so the heart provides more oxygen to your brain and muscles.
  • Causes the liver to release glucose to the blood to obtain energy where needed.
  • Endocrine glands release chemicals called hormones that go into the bloodstream and target other organs or have a specific function on their own. They can produce long-term changes such as puberty and pregnancy and can affect many organs at once.

5. ENDOCRINE SYSTEM

All muscles need to get a good blood supply to bring glucose and oxygen. Remember the by products of respiration but also anaerobic muscle respiration.

Plant hormones are used in food production.

  • increased yield=more food
  • some weed killers actually make the week grow with auxins to a point they die.

No matter how you orientate a seed when planting..., the radicle (the first growth out of the seed) will go downwards and form the root.

Liver cells break down glycogen to glucose

Islets produce glucagon

Blood sugar levels

Example of homeostasis and negative feedback

Blood sugar levels

Islets produce insulin

Liver cells take up glucose and store it as glycogen

If anything goes wrong with insulin production the person shows DIABETES

5.2 THE PANCREAS AND GLUCOSE CONTROL

The hormone-producing cells of pancreas are arranged in Islets, they secrete glucagon or insulin. This is a good example of homeostasis (constant maintenance of the body environment) and negative feedback.

  • nerve fibers: long thin projections of cytoplasm off the cell body.
  • axons: the longest extentions.{can be 1 meter long}
  • dendrites: shorter extensions from the cell body. Function is to pick up electrical signals from other neurons.

Auxins: plant hormones that cause growth. They regulate de geotropism and the phototropism in plants.

Geotropism: response in which a plant grows towards or

away from gravity.

Phototropism?

5.1 adrenal glands and the "fight or flight" hormone

6. Plant hormones

ACCOMODATION

  • the process of the focusing of light coming from different distances on the retina.

Nb: the image on the retina is upside down and the brain converts it to right side up!!

CORNEA & LENS

  • to get a clear sharp image on the retina you must focus the light.
  • both cornea and especially the lens (which changes shape) bends the light rays to a focus on the eye CALLED REFRACTION (*to bend light!!)
  • Ciliary muscle change the shape of the lens, while the suspensory muscle hole the edges of the lens.

EFFECTORS:

  • muscles are effectors because they carry out actions!

Remember the three types of mucles....

Striated(skeletal), Cardiac (specialized-heart only), Smooth (like the iris, diaphragm, alimentary, arteries and veins)

pupil reflex: when the radial muscle of the iris contract quickly causing the pupils to contract(=small).

!!!------>{If a person dies, we say the pupils are fixed and dilated(=large) when light doesn't cause a pupillary reflect!}<------!!!

IRIS: adjusts the amount of light by makin the path hole or pupil smaller or larger. This is accomplished by circular muscles in the iris.

These round muscles are called radial muscles.

The nervous system is necessary to coordinate and regulate body functions!

EYE: know the eye anatomy on figure 10.8 !!!!

Page 131

Cones are found tightly bunched together in the center areas of the retina. Rods on the otherhand, are loosely packed and more around the other areas. So pheripheral vision is B/w! Cones allow sharp vision and more details because they have more pixels(spots).

eyes, tongue, skin, ears, nose

Name the sense organs...

It is the pathway from the sensory neurone to the relay neurone and back to the motor neurone (the motor neurone will tell the muscle to contract=response)

4. Reflex Arc:

Do you need to think about your heart beating?

Do you need to make yourself breathe?

Does your pupil contract and dilate on its own?

Do you need to get telling the food to move along the digestive system?

Do you need to tell your pancreas to make insulin?

How about blinking?

The retina has specialized cells of rods and cones to see black and white shades and color. Rods are B/w and easier to stimulate. You need much more light energy to stimulate the cones to see color.

The conjunctiva gets tears from the tear gland to stay moist. The tears have lysozymes (enzymes that kill bacteria)

What are the senses?

A reflex action = an involuntary response.

Can you think of some other involuntary actions?

What are some examples of a voluntary response???

All receptors are transducers. which

means they convert

one form of energy into another: They convert the energy of the stimulus (such as light energy) into the kind of energy that the nervous system can deal with (electrical impulses).

Topic: 2.50 Receptors and senses: The eye as a sense organ

Learning objectives:

To describe the receptors as the first stage in reflex arcs

To explain that a sense organ combines receptors with: other cells

To assemble the structure and function of the eye

Neurones have a myelin fatty covering or sheath that allows impulses to be carried quickly. The myelin sheath acts as an insulator similar to the rubber around an electrical wire.

TERMS TO KNOW!!!:

muscle tendon

conjunctiva

cornea

iris

pupil

lens

ciliary muscle

suspensory ligament

aqueous humor (has salts to nurish lens)

vitreous humor (fluid is very thick and support shape of eye)

optic nerve

fovea (part of retina where light is focuse when looking straight on an object)

retina (screen at back of eye)

choroid

sclera (very tough-outside of back of eyeball)

iris and pupil

*it is when a stimulus causes you to activate a motor response.

eg: pulling hand away from a hot pan. You don't actually have to think about it as it is a reflex...

What is a reflex?

CO-ORDINATION

So when we feel something with our skin the impulse is detected by the dendrites off the cell body and the impulse continues on through the axon (a for away!) ...

One of the seven characteristics of qualifying to be alive as an organism is:

stimuli: or rather the response to stimulus.....

To response to any sort of sensation you must have......

to CNS

to skin receptor

You need to be able to distinguish between the three neuron types in diagrams of them.

  • Sensory neurones:carry impulses from the sense organs to the CNS (respond to stimulus)
  • Motor neurones: carry impulses from CNS to muscles and glands (effectors)
  • Relay, multi-polar or interneurones: transfer impulses from neurone to neurone. Located in the CNS
  • Dendrites: fibres in contact with other neurones
  • Cell body: it contains the nucleus. Located in brain or spinal cord.
  • Axon: long nerve fibre, it runs in the nerves
  • Myelin sheath: insulates the axon.
  • Synapse: the region where impulses cross from one neurone to the next.
  • Nerve: hundreds of microscopic nerve fibres bundled together, so they are visible. They contain a mixture of sensory and motor fibres.

2. Types of neurons:

5. PERIPHERAL NERVOUS SYSTEM: all of the nerves that connect the body to the central nervous system.

Receptor:

specialized cells of a sense organ which detect a stimulus

4. MOTOR IMPULSES: impulses from CNS to the effectors resulting in an action

3. SENSORY IMPULSES: impulses from sense organs to the CNS, they detect changes in the environment

2. EFFECTORS: glands and muscles. They go into action when they receive hormones or nerve impulses

1. CENTRAL NERVOUS SYSTEM

2. EFFECTORS

3. SENSORY IMPULSES.

4. MOTOR IMPULSES.

5. PERIPHERAL NERVOUS SYSTEM.

1. CENTRAL NERVOUS SYSTEM: formed by the brain and the spinal cord. Nerves carry electrical impulses from it to all parts of the body.

  • Spinal cord: consists of thousands of nerve cells, cell bodies in the grey matter and nerve fibres in white matter.
  • Brain
  • Medulla: involved in reflex actions.
  • Cerebellum: involved in co-ordination.
  • Cerebrum: largest part with two hemispheres, involved in intelligence, memory, skills...

Neurons, like other cells, have

a cell membrane, nucleus, and cytoplasm. The look very different than regular body cells though. They are adapted to carry signal messages quickly.

1. PARTS OF THE NERVOUS SYSTEM

3. PARTS OF NEURONES

To achieve co-ordination within the body we use two systems:

  • Nervous system: sends electrical impulses along nerves. Responses are rapid and precise.
  • Endocrine system: endocrines glands release chemicals called hormones that are carried by the bloodstream until they reach the target organ. They are later inactivated and excreted. Responses are slower.

Glands can be receptors also! If they get a chemical signal [eg a hormone released from another gland]..they might respond and produce their own hormone leading to the production of something...eg. insulin

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