topic 9.4.

Question 1

what is the mammalian nervous system composed of

Answer 1

• central nervous system
• peripheral nervous system

Question 2

what are the three common neurons

Answer 2

• sensory
• relay
• motor

Question 3

sensory neuron

Answer 3

• connects sensory receptors to the CNS through long dendrons
• short axons
• sends electrical impulse from the receptor within the organ/coordination centre

Question 4

relay neuron

Answer 4

• carry action potentials between the sensory and motor neurons
• found within the CNS
• short axons and dendrites

Question 5

motor neuron

Answer 5

• communicates from the CNS to effectors via long axons
• short dendrites
• myelin sheath

Question 6

spinal cord

Answer 6

• cylindrical bundle of nerve fibres runs from brain stem to lower back
• surrounded by spinal vertebrae (protection)
• consists of nerve tissue (neurons, glia, blood vessels).
• 31 pairs of spinal nerves branching out between vertebrae to the body
• made of grey matter surrounded by white matter
• important coordination centre
• actions take place without conscious thought - reflex responses

Question 7

what are reflex responses controlled by

Answer 7

• reflex arc

Question 8

what is the function of the reflex arc

Answer 8

• to bring about appropriate responses to a particular stimulus as quickly as possible without time delay

Question 9

what are two main type of reflexes

Answer 9

• spinal reflexes (hand moves from hot object)
• cranial reflexes (blinking)

Question 10

grey matter

Answer 10

made up of motor nerve cell bodies and relay neurons

H-shaped region

Question 11

white matter

Answer 11

made up of long nerve fibres running the length of the spinal cord

myelinated axons

Question 12

relay neuron

Answer 12

relays impulses from sensory neurons to motor neuron

Question 13

ventral root

Answer 13

carries only motor nerve fibres from spinal cord into spinal nerve

Question 14

motor neuron

Answer 14

carries impulse from spinal cord to effector

Question 15

effector

Answer 15

muscle fibres which contract to move hand away

Question 16

motor end plate in muscle

Answer 16

transfers impulse to effector organ

Question 17

sensory neuron

Answer 17

carries impulse from stimulated sensory recepetor

Question 18

sensory receptor

Answer 18

picks up stimulus

Question 19

spinal nerve

Answer 19

mixed nerves carrying both motor and sensory fibres

Question 20

dorsal root ganglion

Answer 20

contains all the cell bodies of the sensory nerve fibres

Question 21

dorsal root

Answer 21

carries only sensory nerve fibres from the spinal nerve into the spinal cord

Question 22

the brain

Answer 22

• made up of white and grey matter
• grey matter - made of neuron cell bodies
• white matter - consists of nerve fibres

Question 23

medulla oblongata

Answer 23

controls breathing and heart rate

Question 24

cerebellum

Answer 24

controls balance and coordination of movement

Question 25

cerebrum

Answer 25

initiates movement

Question 26

hypothalamus

Answer 26

thermoregulation and osmoregulation

Question 27

peripheral nervous system

Answer 27

divided into two systems; voluntary and autonomic nervous system

Question 28

voluntary nervous system

Answer 28

- motor neurons that are under conscious control involving the cerebrum

Question 29

sympathetic - structure

Answer 29

- myelinated preganglionic fibres leave the CNS & synapse in a ganglion - the ganglia are very close to the CNS - preganglionic fibres are short & postganglionic fibres are long

Question 29

autonomic nervous system

Answer 29

- motor neurons aren't in control of conscious areas of the brain - control bodily functions that are normally involuntary

Question 30

what is the autonomic nervous system divided into

Answer 30

sympathetic and parasympathetic systems

Question 30

During the First World War, some soldiers received head wounds that damaged one side of the cerebellum. Explain why this soldier had problems moving his right arm.

Answer 30

- damage is done to the left side of cerebellum - movement of the right arm is no longer automatic - hence the soldier has to think before moving it

Question 31

parasympathetic - structure

Answer 31

- myelinated preganglionic fibres leave the CNS & synapse in a ganglion - ganglia are near to effector organ - preganglionic fibres are long & postganglionic fibres are short

Question 31

sympathetic - function

Answer 31

- produces noradrenaline at the synapses - main function is to stimulate the bodies fight-or-flight response - rapid response

Question 31

parasympathetic

Answer 31

- produces acetylcholine at the synapses - stimulates bodies “rest and digest” or “feed and breed” response - slower, inhibitory effect

Question 32

compare and contrast the central nervous system and the peripheral nervous system

Answer 32

- both contain nerve cells - both contain synapses - PNS contains sympathetic & parasympathetic system but CNS does not - only the PNS has sensory input and motor output - only the CNS carries out processing of information

Question 33

sympathetic and parasympathetic nervous system act...

Answer 33

...antagonistically

Question 34

state the part of the brain used to think about moving your arm

Answer 34

cerebrum

Question 34

state one function of the cerebellum

Answer 34

- balance - coordination - posture

Question 34

what would lead to an increase in heart rate

Answer 34

- release of noradrenaline by the sympathetic nervous system

Question 35

state the part of the brain responsible for osmoregulation

Answer 35

hypothalamus

Question 36

explain how on a very hot day, the brain ensures that the water potential of the blood remains constant

Answer 36

- sweating occurs causing loss of water from the blood - water potential in the blood falls - osmoreceptors are stimulated - pituitary gland secretes ADH into the blood - causing the kidney tubules to reabsorb more water into the blood