Week 2 - CNS, PNS, glial cells, structures of the brain

Question 1

Central Nervous System

Answer 1

Everything inside the spine and skull
Structures are encased in bone
They are poor at fixing themselves if damaged

Question 2

Peripheral Nervous System

Answer 2

Communication between the CNS and the rest of the body
Everything outside the skull and spine
Made up of nerves (bundles of axons)
It is plastic = it can regrow after damage

Question 3

2 divisions of the PNS

Answer 3

Sensory division - conducts impulses from receptors to the CNS (sends afferent signals to the PNS) (all movements start here)
Motor division - conducts impulses from CNS to effector (efferent signals from PNS)

Question 4

What does the motor division send signals to

Answer 4

Efferent signals to the
Autonomic nervous system (ANS): conducts impulses from the CNS to cardiac muscles - involuntary movement
Somatic nervous system: conducts impulses from CNS to skeletal muscles

Question 5

2 divisions of the autonomic nervous system

Answer 5

Sympathetic nervous system - mobilises body systems during activity
Parasympathetic nervous system - conserves energy and promotes housekeeping functions during rest

Question 6

7 sensory systems

Answer 6

Visual
Auditory
Olfactory (smell) system
Gustatory (taste) system
Tactile (touch) system
Vestibular (organs in inner ear allow for movement)
Proprioceptive (location of muscles and joints in space)

Question 7

2 major cell types

Answer 7

Neurones - nerve cells that are electrically excitable and communicate with other cells via synapses
Glial cells - non neuronal cells in the nervous system that maintain homeostasis, form myelin and provide support and protection for the neurones

Question 8

Make up of a neuron

Answer 8

Dendrites - collect info coming into the cell
Axons are covered in myelin sheath - a fatty sheath that makes electrical signals pass more quickly
Axon terminals connect the dendrites of other neurones and so information is passed through the nervous system
Bundles of axons make up nerves

Question 9

What dictates how much information a cell can process

Answer 9

The size and amount of dendrites

Question 10

Information passed within neurones is

Answer 10

Electrical

Question 11

How does information pass from a cell body to the axon terminal

Answer 11

Using electrical signals called an action potential
1. Signals arrive at the dendrites - these signals change the electrical charge of the cell (up and down)
2. If the charge reaches a set point (threshold), an action potential occurs and travels down the axon)
3. Information is coded by the rate of firing of action potentials

Question 12

Information that passes between neurones is

Answer 12

Chemical

Question 13

How does information pass between neurones

Answer 13

1. When an action potential reaches the axon terminals it causes calcium to enter the terminal
2. This causes synaptic vesicles containing neurotransmitters to bind to the cell membrane and release their contents into the synaptic cleft
3. The neurotransmitter binds to specialist receptors on the dendrites of the neurone
4. If the neurotransmitter is inhibitory this lowers the charge in receiving neurone and if excitatory it increases the charge
5. If the charge in receiving neurone passes threshold the neurone will fire an action potential

Question 14

Inhibitory v excitatory signals

Answer 14

Excitatory currents are those that prompt one neuron to share information with the next through an action potential, while inhibitory currents reduce the probability that such a transfer will take place.

Question 15

5 types of glial cells

Answer 15

Astrocyte
Oligodendrocytes
Schwann cells
Microglia
Ependymal cells

Question 16

Astrocyte

Answer 16

Manage brain environment
Regulates chemicals around neurones, blood flow around brain and nervous system repair, maintain blood-brain barrier.

Question 17

Oligodendrocytes

Answer 17

Form the myelin on axons in the CNS

Question 18

Schwann cells

Answer 18

Form myelin in the PNS
Assist the regeneration and regrwoth of axons

Question 19

Microglia

Answer 19

The brains immune system
Scavenges the CNS for damaged cells and infecting agents

Question 20

Ependymal cells

Answer 20

Make up a membrane called the ependyma, which is a thin membrane lining the spinal cord
They are involved in secreting the cerebrospinal fluid (CSP). They provide the blood CSF barrier

Question 21

What does CSF fluid do

Answer 21

It flows in and around the brain and spinal cord to help cushion them from injury

Question 22

Glial cells involved in the CNS

Answer 22

Astrocyte, oligodendroytes, Microglia, Ependymal cells

Question 23

Glial cells involved in the PNS

Answer 23

Just schwann cells

Question 24

The brainstem sits at the top of the spinal cord and is made up of 3 parts

Answer 24

Medulla oblangata - controls basic motor functions e.g. cardiac (alters heart rate and blood pressure) and respiration (chemoreceptors detect a change in blood and increase breathing rate
Pons - contains nuclei that relay signals from forebrain to the cerebellum
Cerebellum - maintainance of balance and posture, coordination of movements, motor learning

Question 25

Thalamus

Answer 25

Takes information from the periphery and passes it to the cortex

Question 26

Basal ganglia

Answer 26

Series of interconnected nuclei
Stores information about skill learning, movement and habit forming

Question 27

Cerebral cortex

Answer 27

Plays a key role in movement, perception, awareness, attention and memory