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32 Cards in this Set
- Front
- Back
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The nervous system is made up of the central nervous system consisting of the brain and spinal cord and peripheral nervous system consisting of all the nerves connected to the brain and spinal cord. The brain and spinal cord coordinate our responses to stimuli and hence our bodys functions. |
What is the nervous system and peripheral system? |
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A stimulus is anything that an organism responds to.
(Plants respond to light,gravity,air,touch,water and animals respond to light, sound, heat cold, pain, touch, chemicals in the air, chemicals in food.) |
What is a stimulus? |
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1. The brain and spinal cord receive information from recepetor cells located in our sense organs. 2. These receptor cells detect stimuli and send information in the form of an electrical impulse into the CNS along a type of nerve cell called a sensory neuron. |
What are the stages of the brain and spinal cord receiving and sending information? (Part 1) |
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3.The CNS sends information out to an effector which will respond to this stimulus. This info is sent along sent out along a motor neuron.
The effector is a muscle or gland. |
What are the stages of the brain and spinal cord receiving and sending information? (Part 2) |
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A reflex is a rapid automatic response to stimulus. (meaning it happens without having to consciously thinking about it) |
What is a reflex? |
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1. Receptor cells in your skin send an electrical impulse along the sensory neurone to the spinal cord 2.The spinal cord then sends an impulse out through a motor neuron to the bicep muscle which contracts to pull away your hand from the heat or pin which could be damaging to the skin. |
Reflexes are usually protective responses.What happens if someone sticks a pin in your finger ? |
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Sensory neuron (part with the cell body of sendory neurons) Goes to relay neuron(which is in the dark matter) Out through motor neurone to effector. |
What is the pathway of a reflex action? |
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When a person goes from a dark environment and then into bright sunlight the iris responds by making the pupil smaller. This prevents too much light entering the eye and damaging the rods and cones in the retina. |
What happens to the iris with a change in light intensity? |
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This is the ability of the lens to alter its curvature in order to focus light from near or distant objects. |
What is accomodation? |
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Ciliary muscles contract (CCC) Suspensory ligaments slacken so the lens becomes becomes fat and more convex. |
What happens when focusing on a close up object? |
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Light enters the eye in diverging rays. The lens has to refract/bend it a lot in order to focus the light rays onto the retina thus the lens must be fat and more convex. |
Why does the lens have to be fat and more convex? (when focusing on a close object) |
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Ciliary muscles relax. putting tension on the ligaments. Suspensory ligaments tighten Lens is pulled thin and is less convex. |
What happens when focusing on a distant object? |
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Light from a distant object enters the eyes in straight lines. The lens has to refract/bend it very little in order to focus it onto the retina so a thin flat lens is needed. |
Why does the lens have to be thin and less convex? (when focusing on a distant object) |
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They are rods and cones and are located in the retina |
What are light sensitive cells that detect light and where are they located? |
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1.)The radial muscles of iris are relaxed. The circular muscles contract so that the pupil constricts allowing less light so there is a reduced risk of damage to the retina. 2.)The Radial muscles of iris contract. Circular muscles of iris are relaxed. So the pupil dilates allowing as much light as possible. |
The iris controls the amount of light that enters the eye by changing the pupil size. 1.)what happens in Bright Light? 2.)What happens in Dim light? |
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1.The cornea refracts the light and protects the eye 2. The iris controls how much light enters the pupil 3. the Lens focus light onto the retina. 4. The Optic nerve has the bundle of sensory neurones that carry the impulses to the brain. |
1.Cornea 2.Iris 3.Lens 4.Optic nerve |
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5. The retina is the layer of tissue at the back of the eye that contains photoreceptors called rods and cones. 6. The Fovea is the area of retina with the highest concentration of cone cells that provide sharp vision. 7. The Aqueous humour maintains the pressure in the eye and nourishes the cornea. |
5.Retina 6.Fovea 7.Aqueous humour |
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8. the vitreous humour maintains the shape of the eye and attaches to the retina. 9. The ciliary muscles help change the shape of the lens in accommodation. 10. The Sclera is the tough outer layer that extraocular muscles can attach to. 11. The hole in the eye that lets light in |
8.Vitreous Humour 9.ciliary muscles 10.Sclera 11.Pupil |
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Homeostasis is the maintenance of a constant internal environment. A change in the levels of something brings about events which cause a change in the opposite direction. |
Define homeostasis Define negative feedback |
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1. B cells in the pancreas release insulin into the blood. 2.Insulin causes liver and muscle cells to take in glucose from the blood and store it as glycogen 3.Insulin also causes body cells to take in more glucose for respiration. |
The pancreas contains cells which monitor and regulate the blood glucose concentration. What happens when blood glucose concentration is too high? |
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1.a cells in the pancreas release glucagon into the blood. 2.Glucagon causes liver cells to break down stored glycogen and release glucose into the blood. 3.Blood glucose increase to normal. |
What happens when the blood glucose concentration is too low? People who cannot control their blood glucose levels have diabetes. |
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1.Firstly temperature receptors in the skin detect the temperature of the skin and send electric impulses to the hypothalamus 2. When there is a change away from the normal temp then the hypothalamus sends electrical impulses to different parts of the body. |
What happens when the body temperature is changed from the norm. |
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1.The widening of arterioles (Vasodilation) to upper capillaries in the skin b. More blood flows through the upper capillaries. c.More heat energy is lost from the blood to surroundings by radiation. d. This cools the body. |
What happens when the body is too warm? (Part 1) (arterioles) |
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1.Increased sweat production by sweat glands 2.Water from the sweat evaporates from the skin taking heat from the skin 3.This cools the skin |
What happens when the body is too warm (part 2) (sweat) |
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1.The narrowing of arterioles (Vasoconstriction) to upper capillaries in the skin. 2.Less blood flows through the upper capillaries. 3. Less heat energy is lost from the blood to the surroundings by radiation. |
What happens when the body is too cold (Part 1) (arterioles) |
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1.Decreased sweat production by sweat glands. |
What happens when the body is too cold (Part 2) (sweat) |
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1. Erector muscles contract pulling the hairs up. 2. This traps a layer of air close to the skin. 3. The trapped air insulates the skin and reduces heat loss. |
What happens when the body is too cold (Part 3) (Hairs) |
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1. Skeletal muscles make small rapid contractions. This generates heat and raises the body temperature. |
What happens when the body is too cold (Part 3) (shivering) |
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- A chemical substance - produced by a gland - carried by the blood - which alters the activity of one or more targeted organs - and then destroyed by the liver |
What is a hormone? |
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1. Adrenaline is a hormone secreted into the blood by the adrenal glands which are located on top of each kidney |
What is adrenaline? |
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1. Adrenaline causes the heart rate to increase, so muscles are supplied with blood containing glucose and oxygen more quickly. This prepares them for action. 2.Adrenaline stimulates the liver to convert glycogen to glucose and release it into the blood. |
What does adrenaline do? |
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Nervous system - very quick - short lived - electrical impulses - nerves |
Hormonal system - Slower - longer lasting - chemical substance - hormone - blood |
