The Nervous System

Question 1

Define Nerves

Answer 1

The body’s wiring, sending and receiving electrical impulses from all parts of the body. A network allowing communication, coordination and interaction of body tissues and systems and between the body and external environment.

Question 2

What is the order of the Central Nervous System?

Answer 2

1. Central Nervous system (CNS)
2. Peripheral Nervous System (PNS)
   2A. Sensory nerves
   2B. Effector Nerves
   Bi. Somatic
   Bii. Autonomic
   From autonomic is the sympathetic and Parasympathetic

Question 3

What is the characteristics of a Neuron?

Answer 3

Soma (cell body)- which contains the nucleus
Dendrites
Axon
Myelin
Axon Terminal

Question 4

What is the join between the nerves called?

Answer 4

Synapse

Question 5

What is the central nervous system made of?

Answer 5

Brain and Spinal cord. Made of >100 billion neurons.

Question 6

Why do neurons normally look grey?

Answer 6

From lack of Myelin

Question 7

What are the main parts of the brain called?

Answer 7

Cerebrum, cerebellum, diencephalon and brain stem

Question 8

What is the cerebral cortex?

Answer 8

The outer region is the conscious brain.

Question 9

What is the Cerebrum sectioned into?

Answer 9

4 outer lobes and 1 inner lobe

Question 10

What are the specialised neurons called?

Answer 10

Reticular formation

Question 11

What is the role of the brain stem in conduction?

Answer 11

All information from body to brain and vice versa travel via brain stem.

Question 12

Define Sensory pathways

Answer 12

From the body, they are ascending pathways that relay pain, temperature, touch, etc.

Question 13

Define Motor Pathways

Answer 13

Pathways descending to the body.

Question 14

What is the integrative functions undertaken by the brain stem?

Answer 14

Involved in cardiovascular system control, respiratory control, pain sensitivity control, alertness, awareness and consciousness.

Question 15

Where is the spinal cord located?

Answer 15

Within the spinal vertebrae

Question 16

How does the spinal cord create the PNS?

Answer 16

It branches out between each vertebrae

Question 17

What is grey matter?

Answer 17

Unmyelinated axons

Question 18

What is white matter?

Answer 18

Myelin sheath wrapped around axon of neuron

Question 19

How many pairs of nerves are there in the Peripheral Nervous system?

Answer 19

43 pairs
12 cranial pairs
31 spinal pairs

Question 20

What is the Somatic Nervous System?

Answer 20

Voluntarily controlled movements

Question 21

What is the Autonomic Nervous System?

Answer 21

involuntary movements, e.g. heart rate, blood pressure etc.

Question 22

Define Sympathetic

Answer 22

Fight or flight response, Speeds up heart rate etc.

Question 23

Define Parasypathetic

Answer 23

Slows down heart rate etc, rest and recovery

Question 24

Define Motor unit

Answer 24

A single motor neuron and all the muscle fibres it innervates.

Question 25

Why are fine motor movements harder for large muscles?

Answer 25

They usually have one motor movement to hundred of muscle fibres. When one contracts, they all contract.

Question 26

Why are fine motor movements easier for small muscles?

Answer 26

Fine motor control is easier for smaller muscles as one motor neuron can be responsible for innervating just a few muscles fibres.

Question 27

Why are neurons called excitable tissue?

Answer 27

They convert stimuli to electrical signal.

Question 28

Which side are cell membranes on neurons more negative when are rest?

Answer 28

the inside

Question 29

What is the potential difference between the sides called?

Answer 29

Resting membrane potential

Question 30

What is the membrane said to be?

Answer 30

Polarised

Question 31

How is this difference created?

Answer 31

A difference in concentration of potassium ions and sodium ions, inside and outside.

Question 32

What is the sequence of the imbalance maintained during Resting Membrane Potential?

Answer 32

1. Cell membranes are more permeable to potassium ion than sodium ions.
2. Sodium- Potassium actively pumps two potassium ions in for every three sodium ions pumped out.
   Therefore more positively charged ions outside.

Question 33

What is Action Potentials?

Answer 33

Opening membrane channels that allow positively charged ions through can occur in small regions. When a segment of an axon’s sodium ion gates are open, it cannot respond to another stimulus until the gradient imbalance is restored causing the signal to travel only one way.

Question 34

What does the synapse connect?

Answer 34

Neuron to neuron

Question 35

What does the motor end plate connect?

Answer 35

Neuron to muscle fibre, Neuromuscular junctions.

Question 36

What is before the synapse?

Answer 36

Presynaptic terminal

Question 37

What does the presynaptic terminal contain?

Answer 37

Vesicles filled with neurotransmitter

Question 38

How is the action potential transferred across the synapse?

Answer 38

The vesicles release the neurotransmitter across the synaptic cleft. These molecules bind and activate receptors on the post synaptic membrane triggering depolarisation.

Question 39

Define Neuromuscular junction

Answer 39

Depolarisation enters sarcomere via t tubule membranes

Question 40

What is the sequence of Contraction action?

Answer 40

When the signal reaches inside the myofilaments, the electrical charge causes the sarcoplasmic reticulum to release large quantities of stored calcium ions into sarcoplasm.
The Calcium attaches to troponin which wraps the actin molecule. This causes tropmyosin to move, revealing binding sites for the cross bridges to attach.

Question 41

Define reflex reactions

Answer 41

Actions that happen without conscious control that stem from the inhibitory neuron in the spinal cord.