section 3: animal responses - topic 1: the nervous system

Question 1

what is the nervous system split up into?

Answer 1

central nervous system (CNS).
peripheral nervous system (PNS).

Question 2

what is the CNS made up of?

Answer 2

the brain & spinal cord.

Question 3

what is the PNS made up of?

Answer 3

the neurones that connect the CNS to the rest of the body.

Question 4

what are the 2 functional systems of the PNS?

Answer 4

the somatic & autonomic nervous systems.

Question 5

what does the somatic nervous system control?

Answer 5

conscious activities i.e. running, playing video games.

Question 6

what does the autonomic nervous system control?

Answer 6

unconscious activities i.e. digestion, heart rate.

Question 7

what is the autonomic nervous system split into?

Answer 7

the sympathetic & parasympathetic nervous systems.

Question 8

what does the sympathetic nervous system do?

Answer 8

it’s the ‘fight or flight’ system that gets your body ready for action.
sympathetic neurones release the neurotransmitter noradrenaline.

Question 9

what does the parasympathetic nervous system do?

Answer 9

it’s the ‘rest & digest’ system that calms the body down.
parasympathetic neurones release the neurotransmitter acetylcholine.

Question 10

what is the structure of the cerebrum?

Answer 10

the largest part of the brain.
divided into 2 halves called cerebral hemispheres.
has a thin outer layer called the cerebral cortex, which is highly folded.

Question 11

what is the function of the cerebrum?

Answer 11

involved in vision, hearing, learning, thinking.

Question 12

what is the structure of the hypothalamus?

Answer 12

found just beneath the middle part of the brain.

Question 13

what is the function of the hypothalamus?

Answer 13

automatically maintains body temperature at the normal level.
produces hormones that control the pituitary gland.

Question 14

what is the structure of the medulla oblongata?

Answer 14

at the base of the brain, the top of the spinal cord.

Question 15

what is the function of the medulla oblongata?

Answer 15

automatically controls breathing rate & heart rate.

Question 16

what is the structure of the cerebellum?

Answer 16

underneath the cerebrum & also has a folded cortex.

Question 17

what is the function of the cerebellum?

Answer 17

important for muscle coordination, posture, coordination of balance.

Question 18

what is the structure of the pituitary gland?

Answer 18

found beneath (and is controlled by) the hypothalamus.

Question 19

what is the function of the pituitary gland?

Answer 19

releases hormones & stimulates other glands i.e. the adrenal glands, to release their hormones.

Question 20

what is a reflex action?

Answer 20

where the body responds to a stimulus without making a conscious decision to respond.

Question 21

why are reflex actions unconscious?

Answer 21

because the pathway of communication doesn’t involve conscious parts of the brain, instead it goes through unconscious parts of the brain or spinal cord.

Question 22

how are reflex actions protective?

Answer 22

they help organisms to avoid damage to the body because the response happens so quickly.

Question 23

what are 2 examples of reflexes?

Answer 23

blinking reflex.
knee jerk reflex.

Question 24

explain the blinking reflex.

Answer 24

1. stimulus - something touches your eye.
2. receptors - sensory nerve endings in the cornea detect the touch stimulus. a nerve impulse is sent along the sensory neurone to a relay neurone in the CNS.
3. CNS - the impulse is then passed from the relay neurone to the motor neurone.
4. effectors - the motor neurones send impulses to the orbicularis oculi muscles that move your eyelids.
5. these muscles contract, causing your eyelids to close quickly, preventing your eye from being damaged.

Question 25

explain the knee jerk reflex.

Answer 25

1. stimulus - your quadriceps muscle is stretched.
2. receptors - stretch receptors in the quadriceps muscle detect that the muscle is being stretched. a nerve impulse is passed along a sensory neurone.
3. CNS - the sensory neurone communicates directly with a motor neurone in the spinal cord (no relay neurone involved).
4. effectors - the motor neurone carries the nerve impulse to the quadriceps muscle.
5. response - the quadriceps muscle contracts so the lower leg moves forward quickly.