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CO-ORDINATION
Receptor:
specialized cells of a sense organ which detect a stimulus
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
1. CENTRAL NERVOUS SYSTEM
2. EFFECTORS
3. SENSORY IMPULSES.
4. MOTOR IMPULSES.
5. PERIPHERAL NERVOUS SYSTEM.
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.
The nervous system is necessary to coordinate and regulate body functions!
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.
What is a reflex?
*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...
A reflex action = an involuntary response.
Can you think of some other involuntary actions?
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?
Situations in which adrenaline secretion increases
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?
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...
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.
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.
Liver cells break down glycogen to glucose
Blood sugar levels
Blood sugar levels
Islets produce insulin
ACCOMODATION
Nb: the image on the retina is upside down and the brain converts it to right side up!!
CORNEA & LENS
EFFECTORS:
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.
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...
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)
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
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!) ...
You need to be able to distinguish between the three neuron types in diagrams of them.
5. PERIPHERAL NERVOUS SYSTEM: all of the nerves that connect the body to the central nervous system.
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
To achieve co-ordination within the body we use two systems:
What are the senses?
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)
Liver cells take up glucose and store it as glycogen
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:
Islets produce glucagon
Liver cells convert glycogen into glucose
Islets produce insulin
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.
to CNS
to skin receptor
Blood sugar levels
1. CENTRAL NERVOUS SYSTEM: formed by the brain and the spinal cord. Nerves carry electrical impulses from it to all parts of the body.