L21 Nervous Regulation of Physiological Function

Question 1

what feedback mechanism does homeostasis rely on most?

Answer 1

negative feedback - returning a variable to a normal range

Question 2

when does positive feedback occur in homeostasis

Answer 2

rarely, childbirth-pressure, blood clotting and electrical impulses in nerves

Question 3

when does feedforward mechanisms occur in homeostasis?

Answer 3

they anticipate expected change, increased heart rate BEFORE exercise, increased secretion of insulin BEFORE food, gastric secretions BEFORE ingestion of food

Question 4

why do females body water take up less of their weight (50%)?

Answer 4

larger fat to lean ratio of mass

Question 5

what is our total body water TBW?

Answer 5

Men ~ 42L (60% of their weight), this makes up ICF and ECF(plasma and ISF)

Question 6

How is physiological function maintained?

Answer 6

nervous and endocrine system

Question 7

Describe Nervous System

Answer 7

fast acting, hardwired, electrical and chemical signalling, local cellular response and rapid response

Question 8

Describe Endocrine System

Answer 8

slow acting, chemical signalling involving change of gene expression, long lasting responses

Question 9

give an example where nervous and endocrine system co-operate to maintain homeostasis

Answer 9

regulation of blood pressure

Question 10

what is the language of the nervous system?

Answer 10

electrical impulses and generated neurotransmitters

Question 11

give an example of internal stimulus

Answer 11

pressure receptors in blood - blood pressure

Question 12

give an example of an external stimulus

Answer 12

light detected by photoreceptors within eye

Question 13

what does the efferent nervous system consist of?

Answer 13

the autonomic nervous system (parasympathetic and sympathetic/ enteric nervous system the gut) and the motor system

Question 14

why does brain have lots of invaginations?

Answer 14

nerves are present more surface area and room to interact

Question 15

what are cranial nerves part of?

Answer 15

CNS

Question 16

what do cranial nerves consist of?

Answer 16

2 nerves - one sensory, one motor, going in opposite directions

Question 17

what does the olfactory nerve do?

Answer 17

brings info abour smell to olfactory gull

Question 18

what does the cortex control?

Answer 18

motor neurons in eyes - opening of iris to focus light on retina

Question 19

what is a visceral afferent?

Answer 19

incoming pathway to brain from internal organs in body

Question 20

what is a sensory afferent?

Answer 20

incoming pathway from body surface and proprioception such as touch and pain

Question 21

what does the autonomic system do?

Answer 21

regulates smooth and cardiac muscles involuntarily

Question 22

what does the enteric nervous system do?

Answer 22

controls digestive tract, pancreas, gall bladder

Question 23

what does the sympathetic system do?

Answer 23

regulates energy generation aka fight or flight and arousal

Question 24

what does the parasympathetic system do?

Answer 24

has antagonistic effects on target organs - promotes ‘rest and digest’

Question 25

what is a ganglia?

Answer 25

collection of cell bodies in PNS

Question 26

what is a nuclei?

Answer 26

collection of cell bodies in brain/ CNS

Question 27

how do sympathetic and parasmypathetic systems work?

Answer 27

opposingly, most internal/ visceral organs have both nerves present
sweat glands only recieve sympathetic

Question 28

what is a preganglionic fiber?

Answer 28

extends from neuron in CNS, it synapses with cell body of second neuron (efferent)

Question 29

what is a post ganglionic fibre?

Answer 29

it recieves signal from first neuron in CNS via pre-ganglionic fibre and innervates effector organ by post ganglionic neurotransmitters

Question 30

what does dual innervation of organs by both autonomic systems allow?

Answer 30

precise control over organ activity

Question 31

name 2 nerves that are solely sensory

Answer 31

olfactory (smell) and optic (vision)

Question 32

what are the 3 types of motor nerves

Answer 32

alpha, beta and gamma motor neurons