Module 3 Homeostasis and Structure of the Nervous System Flashcards Preview

BM1011 Physiological Systems > Module 3 Homeostasis and Structure of the Nervous System > Flashcards

Flashcards in Module 3 Homeostasis and Structure of the Nervous System Deck (68):
1

Define homeostasis

The body maintaining a constant environment and changes in conditions that challenge its constant environment

2

Stages of maintaining homeostasis

Senses detect changes, integration centres stimulate effectors (interprets signals), effectors respond to changed conditions

3

Define positive and negative feedback

Whether the changes require a positive or negative feedback from body (concept)

4

What is positive feedback

When the environment is stable and constant, the body doesn't have to do anything but continue its processes and maintain

5

What is negative feedback

When theres changes in the environment that the internal environment needs to adjust to and revert back to constant state. Adjustments cease when set point is reached

6

Difference between endocrine and nervous system

endocrine is slow, duration is long and more general, nervous is fast, duration is short more specific

7

What does the central nervous system (CNS) consist of

Brain, spinal cord,

8

what is part of the Peripheral nervous system

all other nervous tissue

9

describe features of the brain

Located in the cranial cavity, surrounded by meninges, bathed in cerebrospinal fluid (the brain moves around in this fluid and provides nutrients), dense collection of neurons (receiving info, integrated and determining what to do), has white matter (cable of information coming in and out of centre) and grey matter (Processing centre).

10

Name the 4 regions of the brain

Cerebrum, Diencephalon, cerebellum, brainstem

11

Which is the largest part of the brain

Cerebrum- generates conscious thought, responsible for memory, reasoning emotions

12

which region of the brain is the main junction for sensory inputs

Diencephalon

13

What is the fluid that protects the brain called and where is it formed

Cerebrospinal fluid, made in ventricles

14

Which region of the brain generates breathing patterns and heart rhythm

Brain stem

15

which cells produce cerebrospinal fluid

ependymal cells

16

which cells protect neurons from bacteria

microglial cells

17

Name the 5 spinal nerves and where they are

cervical(neck), thoracic (chest) , lumbar (abdomen), sacral (pelvis), coccygeal (tailbone).

18

What is a nerve

A collection of neurons

19

Define neuron

functioning cells generating an electrical signal, a nerve is a collection of them.

20

What is afferent

Afferent means it will come out and COME INTO the spinal chord and AFFECT the nervous system. Sensory nerve

21

What is efferent

Efferent is coming out of the central nervous system and is AN EFFECT of the CNS. Motor nerve

22

What parts of the body do spinal nerves receive/ transmit signals to

all over the body not so much the head

23

What parts of the body do cranial nerves receive/transmit signals to

Mostly the head, but vagus goes to all over the body.

24

Name the parts of a neuron

Dendrites, cell body, axon, axon terminal

25

How do neurons generate electrical signals

Occurs because of difference in charge over gradient, cation leaks out of cells and causes a charge

26

What is a voltage difference

Potassium leaks back out causing an imbalance inside becomes negative and outside becomes positive, allows neurons to generate electrical signals

27

How are signals stimulated

dendrites pick up signals, cell body integrates, sends to axon if threshold is reached an action potential is formed

28

where does action potential occur

at axon hillock

29

Where in the spinal cord do sensory neurons enter?

dosal surface (SAD)

30

Where is the most basic integration of sensory input?

at the receptor field and goes into the spinal cord

31

describe the path of a sensory stimulus from receptor ti the sensory cortex

1. receptor field to spinal cord 2. up spinal cord to thalamus 3. thalamus to cortex

32

what is the most basic level of control of the somatic system

spinal cord

33

where in the spinal cord do motor neurons emerge from

ventral- efferent

34

what is the highest level of control of the somatic system

cerebellum

35

what is the parasympathetic system

rest and digest.

36

what are the effects of the cranial nerves

constrict pupils, saliva secretion, nasal secretion

37

what are the effects of the vagus nerve

increase secretion, muscle contraction, relax sphincter , glucose uptake(liver), contracts gallbladder

38

What are the vagus effects on the cardiovascular system

reduce heart rate, constrict bronchioles

39

what is the sympathetic system

fight or flight- from thoracic and lumbar nerves, ganglia in spinal cord or plexus

40

Give an example of negative feedback

Thermorecptors detect temperature, brain integrates signals and alters blood flow, alters muscle activity, alters behaviour, ceases alternation when normal

41

an example of positive feedback

a tear. platelet system: some platelets on site, release chemical to attract more, platelet plug is fully formed.

42

example of endocrine response

blood glucose. pancreas senses glucose, releases insulin, liver stores glucose, tissue takes up more glucose

43

example of nervous response

blood pressure. sensors detect decrease, brain integrates response, HR increases -vasoconstriction, BP returns to normal

44

what is the cation inside the cell

potassium

45

what is the cation outside the cell

sodium

46

how is an action potential formed- basic

axon reaches threshold, tells cell to transmit signal start AP occurs at axon hillock

47

describe the net effect

depolarisation- sodium enters cell, repolarisation - sodium stops entering, potassium leaves, hyper polarisation - too much potassium leaves cell.

48

describe saltatory conduction

Action potential propagating down a myelinated neuron. action potentials in myelinated neurons: gaps in myelin = nodes of Ranvier, AP travels faster down the axon

49

what is absolute refractory period

when an action potential cannot be created, occurs when there is already one in progress

50

what is relative refractory period

when it is difficult to stimulate an action potential (axon less sensitive), when cell is hyper polarised

51

what is a synapse

the gap between the action potential and target cell, signal to release neurotransmitter. neurotransmitter affects target cell

52

describe the components of the synapse

presynaptic neuron, postsynaptic target, synaptic cleft, neurotransmitter, receptor for neurotransmitter

53

describe the conversion of a signal

voltage gated sodium channels open in synapse and lets calcium in = vesicle binds membrane, vesicle releases neurotransmitter to synapse.

54

movement of which ion is mostly responsible for resting membrane potential

potassium and moves out of cells

55

which ion triggers vesicle fusion and neurotransmitter release in the axon terminal

calcium

56

what 5 structures does the cortex have

frontal, parietal, occipital, temporal, insular.

57

what functional areas does the cortex have

sensory, motor, association areas

58

name the functional associated areas

premotor and motor, somatosensory and somatosensory association, primary visual and visual association, auditory and auditory association

59

what is the pre-frontal cortex responsible for

memory and reasoning

60

what is the posterior association responsible for

sensing environment

61

what is the limbic system responsible for

emotions

62

where is the thalamus and what does it do

in diencephalon, relays sensory neuron input to sensory cortex(s)

63

where is the hypothalamus and what does it do

in diencephalon, involuntary signal integration, homeostatic control centre, regulates hormone secretion

64

what does the cerebellum do in terms of regulating signals

fine control of motor activity, received information from sensory receptors, motor cortex and sensory areas, fine tunes motor cortex output

65

what does the brain stem do

controls visual+auditory reflexes, regulates respiratory rate, controls heart rate, blood vessels, generates respiratory and GI reflexes

66

describe how a reflex occurs

reflex is generated in the spinal cord, opposed muscle sets in limbs cause flexion or extension, spinal cord inhibits one set and and stimulates the other to cause withdrawal. In crossed extensor, opposite signals in different limbs causes one to flex and one to extend

67

what does the parasympathetic system do

stimulates secretions from the salivary glands, nose and constricts pupils. reduces cardiovascular and respiratory activity, reduces heart rate and constricts airways. increases gastrointestinal activity, secretion, motility, glucose storage and bladder contractions

68

what effects does the sympathetic system have

increases heart rate, blood pressure, respiration, inhibits gastrointestinal system