Nervous system

Question 1

What is the interstitial space

Answer 1

the space around the cells

Question 2

the nervous system

Answer 2

is the bodys electrical communications network

generates and transmits information throughout the body in the form of electrical impulses

Question 3

CNS and PNS

Answer 3

CNS - brain and spinal cord
PNS - nerves leaving the CNS

Question 4

Central Nervous System

Answer 4

works as control centre
receives information
processes it and sends out instructions

info from receptor cell is transmitted by nerve impulses to the brain

Question 5

Peripheal nervous sytem

Answer 5

whole body is supplied by it
given off as cranial nerves from the brain and spinal nerves from the spinal cord

Question 6

Functions of CNS, PNS

Answer 6

1. sensory input - nerve cells called sensory neurons collect info and transmit impulse

integration - the CNS processes the input

Motor output :
in response, the PNS sends out impulses through motor nerves to muscles, glands and other organs

Question 7

PNS

Answer 7

Cranial nerves

spinal Nerves

Autonomic nerves - supply smooth muscle, cardiac muscle and glands and are under involuntary control. 3 sub divisions
- sympathetic ‘fight or flight’
-parasympathetic
- enteric

Somatic nerves - supply the skeletal muscle and are under voluntary control

Question 8

The nervous system

Answer 8

central NS - body’s master control unity (Spinal Cord, Brain Stem, Brain)

Peripheral NS - the body’s link to the outside world ( The autonomic NS, The somatic NS, Sympathetic NS, parasympathetic, NS

Question 9

Nervous tissue

Answer 9

1. Neurons - responsible for transmission of nerve impulses from one neuron to another via a synapse
2. Neuroglial cells - connective tissue supports the neuron (structurally, by offering essential nutrients, by creating myelin sheaths, by destroying pathogens)

Question 10

what is a Schwann cell

Answer 10

its a neuroglial cell

Question 11

Node of ranvier

Answer 11

between the schwann cells

Question 12

dendrites and cell body

Answer 12

cell body - contains the nucleus, mitochondria and organelles

Dendrites - are extensions that branch from one end of the cell body. They recieve information from other neurons and send impulses towards the cell body

Question 13

Axon

Answer 13

the axon is a cable like projection located on the opposite end of the cell body from the dendrite. The axon carries the impulses away from the cell body and towards the next neuron in the chain

Question 14

Nerve endings / Axon terminals

Answer 14

neuron may connect to
- another neuron (synapse)
- or to a muscle (neuromuscular junction )

Question 15

Neurons can be myelinated or non myelinated

Answer 15

Myelin is a fatty substance that is produced by schwann cells and forms a sheath round myelinated neurons

Question 16

Nodes of Ranvier

Answer 16

gaps in between areas of myleination are called nodes of ranvier

the transmission of nerve impulses is more rapid in a myelinated neuron as the impulses jump from node to node

Question 17

3 types of neuron

Answer 17

1. sensory
2. motor
3. interneurons

Question 18

Sensory Neurons (afferent)

Answer 18

afferent means ( moving towards)

these neurons respond to sensory stimuli detected by the sensory receptor endings

they pass the impulses towards the spinal cord and brain CNS

Question 19

Motor Neurons ( efferent)

Answer 19

Efferent means moving away

transmits impulses from the brain and spinal cord to effector organs and triggering responses from these organs (muscle contraction or release of the glands product)

Question 20

Interneurons or intercalated neuron

Answer 20

also called association or relay neurons

connect neurons to other neurons

lie between a sensory and motor neuron

Question 21

Neuroglial cells

Answer 21

support neurons in several ways, including physically holding them in place and supplying them with nutrients

protect neurons from pathogens and remove dead neurons

certain types of glial cells produce myelin

Question 22

A Nerve

Answer 22

a nerve is a bundle of neurons

An individual axon plus its myelin sheath is called a nerve fibre

Nerves provide a common pathway for the electrochemical nerve impulses

Question 23

Nerve fibres can be of three types

Answer 23

Motor - which send impulses away from the CNS

Sensory - which send impulses towards the CNS

Mixed - carry both sensory and, motor fibres

Question 24

Visceral sensory and motor nerves

Answer 24

associated with organs and body systems - involuntary control

Question 24

Somatic sensory and motor nerves

Answer 24

Associated with the somatic structures (muscles, joints, tendons). Voluntary control

Question 24

Nerve impulse conduction

Answer 24

at the end of the neuron there is a gap before the next cell if the next cell is another neuron, the gap is known as a synapse if the next cell is a muscle cell, the gap is known as a neuromuscular junction the neuron before the synapse is known as the presynaptic neuron, the neuron after the synapse is postsynaptic

Question 25

Neurotransmitters

Answer 25

Travel between neurons at the synaptic cleft (gap between neurons) - Acetylcholine - Adrenaline - dopamine - serotonin

Question 26

Impulse conduction simplified

Answer 26

1. calcium - gated channels open 2. calcium ions enter the synaptic terminal and cause the release of a chemical called a neurotransmitter 3. the neurotransmitter diffuses across the synapse to the next cell 4. this stimulates sodium channels to open in the postsynaptic membrane

Question 27

nerve impulses

Answer 27

nerve impulses are electrical in nature depolarisation - generation of electrical impulse repolarisation - recharging Nerve impulses are an ' all or nothing' phenomenon. The nerve is either stimulated (depolarised) or not

Question 28

Nerve impulses (polarised)

Answer 28

NB - electrolytes carry a charge we could refer to this state as polarised - meaning big difference

Question 29

depolarization of a neuron

Answer 29

- sodium channel opens on neuron cell membrane - sodium ions flow into cell by passive diffusion - increase in sodium leads to a positive electrical charfe

Question 30

repolarization of a neuron

Answer 30

- sodium channels close - k+ channels open - k+ diffuses out of the cell - resting state restored as repolarization ends, sodium - potassium pump moves sodium and potassium ions back to their original sides

Question 31

Cranial nerves

Answer 31

12 pairs of cranial nerves that emerge directly from the brain and brain stem cranial nerves are referred to in roman numerals exit the skull via foramen each pair is dedicated to particular functions

Question 32

Cranial Nerves

Answer 32

some have a sensory fucntion - bring info from the sense organs to the brain others have a motor function - control muscle, tissue and organ activity some have mixed sensory and motor functions