neuronal communication

Question 1

What term is used to describe communication between adjacent cells or cells at a distance?

Answer 1

cell signalling

Question 2

what is the speed, duration and distribution of responses caused by hormones

Answer 2

Hormones usually produce a response that is long-lasting, slow, and widespread.

Question 3

what is the speed, duration and distribution of responses caused by nerve impulses

Answer 3

Nerve impulses produce responses that are usually localised, short-lived and rapid.

Question 4

what is a receptor

Answer 4

A cell or protein that detects one specific type of stimulus.

Question 5

what is an effector

Answer 5

A part of the body, often a muscle or gland, that produces a response to a stimulus.

Question 6

what is the role of receptors in homeostasis

Answer 6

To detect changes in a specific stimulus involved in a physiological process.

Question 7

State the name of the cell which produces the sleeve of protein and fatty material which covers some neurones.

Answer 7

Schwann cell

Question 8

what do myelin sheaths do

Answer 8

acts as an insulating layer and allows myelinated neurones to conduct the electrical impulse at a faster speed, impulse jumps from the nodes of ranvier

Question 9

why is the nerve impulse slower moving in non-myelinated neurones

Answer 9

signal cant ‘jump’ from the nodes of ranvier and instead has to transmit continuously along the nerve fibre so is slower

Question 10

What term is used to describe the period of time when a neurone is unable to repeat an action potential?

Answer 10

refractory period

Question 11

Describe how voltage-gated channels and the movement of sodium ions prevent the generation of an action potential during the refractory period.

Answer 11

The voltage gated sodium channels are closed, preventing movement of sodium ions into the axon. This stops the generation of an action potential.

Question 12

why should a refractory period follow an action potential

Answer 12

It ensures action potentials are unidirectional and occur as discrete impulses.

Question 13

What method of conduction in myelinated axons involves action potentials jumping from one node of Ranvier to the next?

Answer 13

saltatory conduction

Question 14

what are the three factors that affect speed of conduction along an axon

Answer 14

temperature, axon diameter and myelination

Question 15

What name is given to the swollen end of a presynaptic neurone?

Answer 15

synaptic knob

Question 16

Which neurotransmitter is found in cholinergic synapses?

Answer 16

acetylcholine

Question 17

Name the two categories synapses can be placed in, based on how they affect the likelihood of an action potential occurring.

Answer 17

excitatory and inhibitory

Question 18

what is summation

Answer 18

describes the process in which more than one impulse is needed to generate an action potential at a synapse

Question 19

what is temporal summation

Answer 19

process by which an action potential is generated from a single presynaptic neurone releasing neurotransmitters a number of times.

Question 20

what is spatial summation

Answer 20

process by which an action potential is generated from multiple presynaptic neurones releasing neurotransmitters.

Question 21

what does the cerebrum control

Answer 21

learning memory and conscious thought

Question 22

what does the cerebellum control

Answer 22

unconscious actions such as balance and posture

Question 23

what does the hypothalamus control

Answer 23

regulatory centre for temperature and water balance

Question 23

what does the medulla oblongata do

Answer 23

breathing and heart rate

Question 24

what does the pituitary gland do

Answer 24

stores and secretes hormones

Question 25

what are the three types of muscle found in the body

Answer 25

cardiac, skeletal and smooth muscle.

Question 26

what type of muscle is under voluntary control

Answer 26

skeletal

Question 27

what type of muscle has the slowest contraction speed

Answer 27

smooth

Question 28

which muscles are striated

Answer 28

cardiac and skeletal

Question 29

which type of muscle is branched

Answer 29

cardiac

Question 30

which type of muscle is multinucleated

Answer 30

skeletal

Question 31

which type of muscle can remain contracted for long periods of time

Answer 31

smooth

Question 32

what is neuromuscular junction

Answer 32

where a motor neurone meets a skeletal muscle fibre

Question 33

which ions are released when an action potential meets a neuromuscular junction

Answer 33

calcium ions

Question 34

what does acetylcholinesterase do

Answer 34

hydrolyses acetylcholine to choline and ethanoic acid which diffuse across the synaptic cleft into the presynaptic neurone, which allows for recycling and prevents it continuously creating an action potential in the postsynaptic neurone

Question 35

what is actin

Answer 35

forms the thin protein filaments in myofibrils in muscle fibre

Question 36

what is myosin

Answer 36

forms the thick protein filaments in myofibrils in muscle fibre

Question 37

what is a sarcomere

Answer 37

the distance between adjacent Z-lines on a myofibril

Question 38

What is the name of the band on a sarcomere where actin and myosin do not overlap?

Answer 38

i-band

Question 39

What is the name of the band on a sarcomere where actin and myosin do overlap?

Answer 39

a-band

Question 40

What change occurs when an ATP molecule binds to the myosin head during muscle contraction?

Answer 40

the myosin head moves away from the actin filament

Question 41

What change in the myosin head takes place when energy is released by the hydrolysis of ATP?

Answer 41

The myosin head changes its angle causing it to return to its
original position.

Question 42

the order of neurones that a signal travels across

Answer 42

sensory, relay and motor

Question 43

what happens when calcium ions are released into the synapse

Answer 43

they diffuse into the synaptic knob and cause synaptic vesicles to fuse with the presynaptic membrane