Nervous System

Question 1

What are the Divisions of the nervous system

Answer 1

central nervous system
peripheral nervous system
somatic nervous system
autonomic nervous system
sympathetic nervous system
parasympathetic nervous system

Question 1

Cerebrum

Answer 1

largest part of the brain
2 hemispheres - connected by the corpus callosum

Question 2

Frontal Lobe

Answer 2

Motor cortex
Broca’s area in the dominant hemisphere
intellectual and emotional behaviour
thinking and memory

Question 3

Parietal Lobe

Answer 3

sensory cortex
language and touch

Question 4

Temporal Lobe

Answer 4

auditory cortex
learning
judgement
feelings

Question 5

Occipital Lobe

Answer 5

Visual cortex

Question 6

Brainstem

Answer 6

contains medulla oblongata
responsible for breathing, HR and temperature
pons lies between the midbrain and medulla oblongata

Question 7

Cerebellum

Answer 7

contains half the brains neurons
responsible for posture, balance and coordination

Question 8

Blood Brain Barrier

Answer 8

protects brain cells from pathogens and harmful substances.

There is an extra layer of endothelial cells around the capillaries preventing blood from leaking from them, also a thick basement membrane and astrocytes

Question 9

What protects the spinal cord?

Answer 9

spinal vertebrae, tough connective tissue and meninges

Question 10

Spinal Cord Overview

Answer 10

extends from medulla to the superior border of the second lumbar vertebrae

two enlargements: cervical (nerves for upper limbs: C4-T1) lumbar (nerves for lower limbs: T9-T12)

Grey matter is arranged in a H shape with white matter surrounding it

31 pairs of spinal nerves

Question 11

Layers of the spinal cord and brain

Answer 11

Dura mater: durable, fibrous and dense connective tissue. green in colour

subdural space

Arachnoid mater: vascular but no muscles. pink in colour

subarachnoid space

Pia mater: thin and transparent connective tissue that adheres to the surface of the spinal cord and brain. red in colour

Question 12

Neuroglia

Answer 12

cells that support and protect nerve cells

Question 13

Parts of a nerve cell and their function

Answer 13

Cell body: contains everything that keeps the cell alive (mitochondria, nucleus etc)

Dendrites: receive impulses and transmit them along the neuron

Axon: transmit impulses away from the cell body

Myelin Sheath: protects the axon and provides electrical insulation. gaps in the myelin sheath are called the nodes of ranvier

Axon terminals: where an axon ends and action potentials are passed on to adjacent neurons via synapses.

Question 14

SAME acronym

Answer 14

Sensory Afferent
Motor Efferent

Question 15

how many pairs of cranial nerves are there

Answer 15

12

Question 16

Brief overview on how the somatic nervous system works

Answer 16

stimuli is picked up by receptors which stimulates afferent sensory neurones. impulse travels to the CNS and then efferent motor neurons cause a gland or effector to react.

Question 17

Functions of the enteric nervous system

Answer 17

controls gut function
monitors chemical changes in the GI tract
controls smooth muscle
governs secretions

Question 18

functions of the autonomous nervous system

Answer 18

regulates and maintains homeostasis
blood pressure, HR, temperature, breathing, digestion, metabolism and elimination.

Question 19

sympathetic nervous system

Answer 19

fight or flight, expenditure of energy

Question 20

parasympathetic nervous system

Answer 20

relaxation, conservation of energy

Question 21

How is the resting potential formed

Answer 21

most sodium is outside the cell and most potassium is inside.
3 sodium leave and 2 potassium enter via the sodium potassium pump = outside of the cell is more positive
potential difference is around -5mV but it needs to be around -70mV
there are potassium channels in some nerve and muscle cells so some diffuses out

Question 22

How is an action potential created?

Answer 22

excitatory neurotransmitters bind to receptors which results in sodium diffusing into the neuron - making that part of the neuron more positive

-55mV is the threshold for voltage gated sodium channels to open further down the axon

when the voltage reaches 30mV the voltage gated sodium channels close but voltage gated potassium channels open so potassium ions diffuse out

so much potassium diffuses out that the voltage goes lower than the resting potential in a process called hyperpolarisation (-90mV) and another impulse cannot be sent during this time

Question 23

3 facts about action potentials

Answer 23

either generated or not “all or nothing principle”

which means all action potentials are the same size (more painful stimulus = higher frequency of action potentials)

always travel in the same direction

Question 24

Schwann Cells

Answer 24

Surrounds the axons of neurons in the peripheral nervous system forming the myelin sheath

this speeds up conduction of action potentials as they jump along the nodes of Ranvier

Question 25

Factors that can affect the rate of saltatory conduction

Answer 25

The condition of the myelin sheath

temperature

diameter of axon

Question 26

What happens at synapses?

Answer 26

Vesicles containing neurotransmitters come towards the axon terminals of the presynaptic neuron

neurotransmitters enter the synaptic cleft via exocytosis after calcium enters

receptors receive the neurotransmitters on the dendrite of the post synaptic neuron (which are also sodium channels - so sodium also enters the neuron)

action potential continues in this neuron

Question 27

What type of synpase is acetylcholine used at?

Answer 27

Cholinergic

Question 28

How does ipratropium bromide link to synapses?

Answer 28

ipratropium bromide is anti cholinergic, so it stops acetylcholine having it’s effect (muscle contraction) - so in cases of COPD it relaxes the airways