Principles of Nervous System Flashcards
1
Q
List 3 features/functions of the Soma/cell body of a Neuron
A
- It contains the nucleus
- Synthesis of proteins/ion channels (lots of ER)
- Important for cellular metabolism (lots of mitochondria)
2
Q
List 3 features/functions of dendrites of a Neuron
A
- Receives inputs
- Convey information towards Soma
- Large surface area for synapse formation
3
Q
List 3 features/functions of Axon Hillock of a Neuron
A
- it is the Origin of the axon
- It is very excitable
- Action potential originates here
4
Q
List 2 features/functions of Axon/nerve fibre of the neuron
A
- It transmits action potential
2. Usually only one (although often branches)
5
Q
What is the function of the Axon terminal of a neuron
A
- it synapses on other neurons, effector organs or forms specialised sensory endings
6
Q
An axon can also be called
A
Nerve fibre
7
Q
What is the cell body of a neuron called
A
Soma
8
Q
List 3 types of neuron with explanation + where they can be found
A
- Unipolar - Has one axon only. E.g primary sensory neurons in Dorsal root ganglia (close to invertebrae)
- Bipolar - Has one axon and one dendrite. E.g Specialised sensory neuron in retina
- Multipolar - Has one axon and multiple dendrites. E.g motor neurons and majority of neurons in the brain
9
Q
List 2 forms of Axons
A
- Myelinated Axon
2. Unmyelinated Axon
10
Q
List 3 features of a myelinated Axon
A
- Enables saltatory conduction- Action potential passes from node to node
- Very rapid (120m/s)
- Less than 1 micro-metre in diameter
11
Q
List 2 features of unmyelinated axon
A
- Very slow (1.5m/s) e.g pain fibre
2. Less than 1 micro-metre in diameter
12
Q
In a nerve impulse/Action potential. What is Saltatory Conduction?
A
Saltatory Conduction occurs in myelinated Axon. It involves the conduction(travelling) of a nerve impulse/AP by leaps from one node of ranvier to the next.
13
Q
In an Axon, what is a Node of Ranvier?
A
Node of Ranvier is the gap between myelin sheaths on an axon.
14
Q
In Axons, list 2 directions of conductions, explaining what it means with an example
A
- Afferent - An axon that carries an impulse towards the CNS. E.g primary sensory neurone
- Efferent - An axon that carries an impulse away from the CNS. E.g a Motor neurone
15
Q
What is a synapse ?
A
A junction between an axon terminal and a target cell (neuron dendrite or a neuromuscular junction)
16
Q
List 2 types of synapses
A
- Electrical synapse - usually in the brain
2. Chemical synapses
17
Q
How does a chemical synapse works
A
- Uses neurotransmitters e.g acetylcholine
- Depolarisation of presynaptic membrane causes Ca2+ ion channels to open
- Vesicles fuse to presynaptic membrane and release neurotransmitters
18
Q
List 3 types of Neuroglia cells of the C.N.S
A
- Astrocytes
- Oligodendrocyte
- Microglia
19
Q
List 6 functions of Astrocytes
A
- Provide structural support
- Supply nutrients (glucose)
- Maintain ionic environment (remove k+)
- Repair of the nervous system
- Neurotransmitter uptake
- Form barriers around vessels
A: Please Shut My Runny Nose
20
Q
List one function of Oligodendrocyte
A
- Production and maintenance of myelin sheath. One oligodendrocyte myelinates multiple axons.
21
Q
What are microglia?
A
They are immune cells
22
Q
List 3 functions of microglia (immune cells)
A
- They are phagocytic (like macrophage)
- Cytotoxic (release hydrogen peroxide)
- Promote repair
They release cytokines/chemokines
PCR - Phagocytic, Cytotoxic, Repair Like GPCR (except no G)
23
Q
List one Neuroglia of the P.N.S and explain 3 of its function
A
- Schwann cells -
- it myelinates axons (spiral wrapping).
- It is important for regeneration
- They are also immune cells. They release cytokines/chemokines
One Schwann cell myelinates one axon
24
Q
Name 2 cells in the CNS that can act as immune cells by secreting soluble mediators (cytokines/chemokines)
A
Neuroglia in CNS -Microglia
Neuroglia in PNS - Schwann cells
25
The brain is divided into 3 sections. List them
1. Forebrain
2. Midbrain
3. Hindbrain
26
The Forebrain is divided into 3 sections. List them
1. Cerebral hemispheres(Cerebrum)
2. Thalamus
3. Hypothalamus
27
The brain stem is made up of
1. The Midbrain
| 2. The Hindbrain
28
The Cerebral hemisphere is divided into 4 lobes. List them
1. The Frontal lobe
2. The Parietal lobe
3. The Temporal lobe
4. The Occipital lobe
29
List 3 things the grey matter in the cerebral cortex is made up of
1. Neuronal cell bodies
2. Synapses
3. CNS Neuroglia cells
30
The white matter in the brain is made up of
1. Myelinated axon
31
The Hindbrain is made up of
The Cerebullum
32
What is the cerebral cortex?
It is present in the cerebral hemisphere(cerebrum). It is the outer grey matter (made up of neuronal cell bodies,neuroglia and synapses)
33
What is the Frontal lobe involved in
F for F
*Frontal for Fast motion*
Primary motor complex.
Skeletal motion
34
What is the Parietal lobe involved with
P for P
*Parietal for Pain*
Primary somatosensory cortex.
Pain, touch and proprioception information for muscles and joints
35
What is the Occipital lobe involved with
*Occipital for Optham-*
Primary visual cortex
-Eye processes
36
What is the Temporal lobe involved with
```
*Temporal for TEN*
TEN for Tongue(Taste), Ears(Auditory) and Nose(Olfactory)
-Primary auditory cortex
-Primary olfactory cortex
-Taste
```
37
What is the function of the Thalamus
It is centrally located
So it is the relay centre of the brain
(sensory information passes through the thalamus before reaching the cortex of the brain)
38
What is the function of the Hypothalamus
It is important in homeostasis
- It controls Autonomic N.S (Functions of organs)
- Controls Endocrine system (secretion of hormones)
It sits below the thalamus
39
What is the brainstem made up of ?
1. The Midbrain
| 2. The Hindbrain (bar the cerebellum)
40
What is the function of the brainstem
1. Connects the cortex to the spinal cord
2. Controls respiration and the cardiovascular systems
-Damage to the brainstem will most likely be fatal
41
List 1 Function of the Cerebellum in the hindbrain
The cerebellum co-ordinates muscular activity, It is involved in fine motor movements e.g playing a violin/delicate eye movements
42
Where does the spinal cord end in relation to the vertebrae/spine?
Ends in the first Lumbar (L1)
| Starts in Atlas (just above C1)
43
Where does the spinal cord sit?
In the vertebral canal
44
List 3 functions of the spinal cord
1. They are involved in reflexes
2. They convey information from the Brain to the PNS (motor)
3. They convey information from the PNS to the brain (sensory)
45
The spine is divided into 5 segments. List them
1. Cervical segment (C1-C7)
2. Thoracic segment (T1-T12
3. Lumbar segment (L1-L5)
24
4. Sacrum (5 bones)
5. Coccyx (4 bones)
9
33 in total
46
Explain the anatomy of the spinal cord, referring to the grey and white matter
Unlike the cerebral cortex, The grey matter in the spinal cord is in the inner core, while the white matter is on the outer core.
Grey matter is made up of neuronal cell bodies
White matter is made up of myelinated axons which conveys information to/from the brain
47
What is the function of the peripheral nervous system
Connects the CNS to the periphery
| Nerve supply to muscles glands, skins, vessels and viscera
48
List 5 tissues/organs that a nerve can supply
1. Muscle(T)
2. Glands (O)
3. Vessels(O)
4. Skin(O)
5. Viscera (T)
49
List 2 components of the PNS
1. Somatic (Voluntary) component - skeletal muscles, exteroception, proprioception
2. Autonomic (Involuntary) component - organs, vessels
50
Are somatic component and autonomic component of PNS always anatomically separate?
No. Many peripheral nerves contains axons from both components
51
Peripheral nerves are grouped into 2. List them
1. Cranial Nerves (only 12, all innervate in the head and neck)
2. Spinal Nerves
52
Peripheral nerves arises from 2 locations. List them
1. Brain/brainstem - Cranial nerves (only 12, they all innervate in the head and neck)
2. Spinal cord - Spinal nerves
53
Cranial nerves supplies …..
1. The Head
| 2. The Neck
54
Spinal Nerve supplies.....
1. The whole body (bar the head and neck)
| with somatic motor and somato-sensory supply
55
How many spinal nerves are there
```
31 pairs
8 in Cervical (c1-7 nerves exit above vertebrae. c8+ exit below)
12 in Thoracic
5 in Lumbar
5 in Sacrum
1 in Coccyx.
```
56
What are nerve roots
Nerve roots connect spinal nerves to the spinal cord
57
List 2 types of nerve roots
1. Dorsal root
| 2. Ventral root
58
What direction does a reflex travel in the spinal cord
From the back (Dorsal - somatosensory - Afferent) to the Front (Ventral - Somatic motor - Efferent)
59
What is a Ganglia?
A cluster of cell bodies
60
Spinal nerves are mixed nerves. True or False
True. Mixed of somatosensory (Dorsal), somatic motor (Ventral) and sympathetic (Ventral)
61
How does the spinal nerve exit the vertebral
Through the intervertebral foramen
62
List 3 features of a spinal nerve
1. They are Segmentally Organised
2. Spinal nerves are Mixed nerves
3. Spinal nerves are very Short
SO-M-S
63
From the Nerve roots (Dorsal&Ventral), the spinal nerve forms . The spinal nerve then divides into:
The primary rami
- The Dorsal primary ramus
- The Ventral primary ramus
64
List 3 parts the dorsal primary ramus supplies
1. Skin over the paravertebral gutter
2. Erector spinae muscles
3. Facet joints of vertebral column
65
Where does the ventral primary ramus supply
supplies rest of the body(except head and neck)
| It is a much larger nerve than the dorsal primary ramus
66
What is a nerve plexuses
A nerve plexuses is when ventral primary ramus merge to form nerves that contains axons from multiple spinal nerves
67
Ventral primary ramus forms 5 nerve groups. List them
1. Cervical plexus
2. Brachial plexus
3. Intercostal nerves
4. Lumbar plexus
5. Sacral plexus
68
Why are nerve plexus important
They supply nerves (innervation) to large muscle groups (limbs)
69
Segmentation of spinal nerves results into 2 groups
1. Dermatomes
| 2. Myotomes
70
What is a Dermatome?
A dermatome is an individual strip of skin that is innervated by a single spinal nerve (primary rami)
71
What is a Myotome?
A myotome is an individual muscle group that is innervated by a single spinal nerve (primary rami)
72
Spinal nerves belong to which germ layer
A. Ectoderm
B. Mesoderm
C. Endoderm
A. Ectoderm
One pair of spinal nerve(ectoderm) grows into one pair of somites (horizontal mesoderm that forms the dermatome and myotome)
73
What are somites
Mesoderm germ layer. Of which dermatomes and myotomes develop from
74
In the dermatome region surrounding the umbilical cord. What spinal nerve supplies that dermatome?
T10
75
What is the clinical importance of Dermatomes
A loss of sensation/pain in the skin of the dermatome can be referred to the region of spinal cord, nerve root or spinal nerve that supplies that dermatome region.
EASY TO DETECT LOCATION OF INJURY FROM DERMATOME
76
The T1-11 intercostal nerves can supply the T1-11 dermatome and T1-11 Myotome. True or False
True
77
List 2 functions of the Autonomic component of the PNS
1. Regulates operations of the internal organs
| 2. Maintains the internal environment
78
The Autonomic component (ANS) is divided into 2. List them
1. Sympathetic
| 2. Parasympathetic
79
Function of the Sympathetic division of the ANS
1. Involved in Flight or Fight
| 2. Maximises use of metabolic resources
80
Function of Parasympathetic division of the ANS
1. Switched on during resting
| 2. Increases/conserves metabolic resources
81
Describe the anatomy of ANS
Preganglionic neuron - Autonomic ganglia - synapse - Postganglionic neuron - effector organ (e.g gland, smooth/cardiac muscle- not skeletal (that is somatic/voluntary)).
This occurs except in sympathetic supply to the adrenal medulla (present in the adrenal gland in the kidney).
Only preganglionic axon present. For quick secretion of adrenaline in a fight/flight response.
82
For nerve supply to the abdomen.
| What 2 distinctive stops. Does it have to pass through
1. The Splanchnic nerves
| 2. The prevertebral ganglia
83
All preganglionic sympathetic axon enters the sympathetic trunk. True or false?
True
84
The postganglionic axon that goes to the musculoskeletal system exit through branches. True or False?
False.
They exit through the spinal nerve. Whilst the postganglionic axons that goes to the head, lungs and heart exit through branches
85
In relation to length, in parasympathetic pathway from the brain stem and sacral nerves. What is the difference between the preganglionic axon and postganglionic axon
The preganglionic axon is much longer than the postganglionic axon as the Post is much close to the effector organs they act on
86
In parasympathetic pathway, list 2 nerves that originates from the brain stem and name their destinations
1. Cranial nerve - Head i.e Pupil, lacrimal gland (tears prod.), parotid/submandibular gland (saliva prod)
2. Vagus nerve - Lungs, heart and abdominal vessels
