Unit 4

Question 1

Clearly distinguish between afferent nerves and efferent nerves.

Answer 1

Afferent: carries electric nerve impulses towards the CNS frin receptors.
Effrent: carries away from the CNS to muscles and glands.

Question 2

Use anatomical information to clearly distinguish between the central nervous system and the peripheral nervous system.

Answer 2

The CNS consists of the brain and spinal cord.
(Center of the body)
The PNS consists of the cranial nerves, spinal nerves, ganglia, exteric plexuses and sensory receptors.
(Extremetiesi of the bodies)

Question 3

Clearly distinguish between the main function(s) of the central and peripheral nervous systems.

Answer 3

Your central nervous system includes two organs, your brain and spinal cord. Your peripheral nervous system is everything else and includes nerves that travel from your spinal cord and brain to supply your face and the rest of your body

Question 4

Compare and contrast (list both similarities and differences between) the sympathetic nervous system and the autonomic nervous system.

Answer 4

Similitarities are that they are involuntary responses.
The autonomic nervous system comprises two parts- the sympathetic and parasympathetic nervous systems. The sympathetic nervous system activates the fight or flight response during a threat or perceived danger, and the parasympathetic nervous system restores the body to a state of calm.

Question 5

Compare and contrast the sympathetic division of the autonomic nervous system and the parasympathetic division of the autonomic nervous system

Answer 5

They are both part of the autonomic nervous system which are both involuntary.

Sympathetic (fight or flight) Emergency system (“fight or flight”)

Increase heart rate

Vasoconstriction

Bronchodilation

Decrease peristalsis

Increased sweat gland secretion

Parasympathetic (rest + digest bitch)

Control under normal conditions (“rest and digest”)

Decrease heart rate

Increase peristalsis

Increase digestive juice secretion

Micturition reflex

Question 6

Clearly distinguish between nerves and neurons.

Answer 6

Neurons are specialized to transmit information throughout the body. Whereas nerve is a whitish fibre or bundle of fibres in the body made up of number of neuron cells that transmits impulses of sensation to the brain or spinal cord, and impulses from these to the muscles and organs.

Question 7

Clearly distinguish between afferent nerves and efferent nerves.

Answer 7

Afferent: carries electric nerve impulses towards the CNS frin receptors.
Effrent: carries away from the CNS to muscles and glands.

Question 8

. Clearly distinguish between a nerve and a plexus.

Answer 8

A plexus is a bundle of intersecting nerves, blood vessels, or lymphatic vessels in the human body.

A nerve is a bundle of fibers that receives and sends messages between the body and the brain.

Question 9

Describe the cellular structure of a myelinated motor neuron, including the names and structural
features of dendrites, axons, cell bodies, and the myelin sheath.

Answer 9

Cell body: holds the majority of the cellular organelles

Dendrite: cytoplasmic processes conducting impulses toward the cell body.Usually short, branched fibers

Axon: Conducts impulses away from cell body
Usually a single, long process

Myelin sheath: A white fatty coating around axons of neurons. Formed from oligodendrocytes (central nervous system) and Schwann cells (peripheral nervous system). The myeline sheath increases the impulses of conduction.

Question 10

Name and describe the general structure of the cells that provide the myelin sheath in neurons of the:
a. Peripheral nervous system
b. Central nervous system

Answer 10

a. schwann cells
b. oligodenrocytes

Question 11

Organization of neurons in the PNS + CNS

Answer 11

In the PNS,
Groups of cell bodies are called ganglia (ganglion)
Groups of axons are called nerves

In the CNS,
Groups of cell bodies are called nuclei (nucleus) or gray matter
Groups of axons is called a tract
A group of tracts is called white matter(due to the myelin sheaths covering the axons)

Question 12

Name the most abundant (by numbers) cell type of the nervous system, and describe the primary function of this cell type.

Answer 12

astrocytes (Glia cells aka ganglions)

Question 13

Pathway for control of movement

Answer 13

The direct pathway of movement is a neuronal circuit within the central nervous system (CNS) through the basal ganglia which facilitates the initiation and execution of voluntary movement.

Question 14

Describe the neural pathways involved in the reception and transmission of somatosensory information.

Answer 14

The somatosensory system consists of the two main paired pathways that take somatosensory information up to the brain: the medial lemniscal or posterior pathway, and the spinothalamic or anterolateral pathway. The somatosensory pathways are made up of a relay of four neurons

Question 15

Cerebrum function

Answer 15

Controls our ability to read, write, speak, think, remember, feel, and move
Interpretation of sensory information
Motor function
Four external lobes: frontal, parietal, temporal and occipital lobes

Question 16

Diencephalon function

Answer 16

Central core of the forebrain
Main parts: thalamus and hypothalamus

Question 17

Thalamus function

Answer 17

Egg-shaped structure
Receives and passes on sensory information (e.g., pain, temperature, light touch, pressure) i.e., afferent transmissions
Sorts out, edits and relays impulses of similar function
Associated with the interpretation of pain and pleasure

Question 18

Hypothalamus function

Answer 18

Under the thalamus
Controls :
autonomic nervous system (involuntary transmissions from the central nervous system)
Heart rate, body temperature, movement of food, appetite, thirst, sleep (aka. Homeostasis)
production of hormones by acting on the pituitary gland

The hypothalamus is the principle intermediary between the nervous and endocrine systems

Question 19

Brain stem consists of?

Answer 19

Midbrain
Pons
Medulla Oblongata

Question 20

Brain Stem function

Answer 20

The section between the brain and spinal cord
Controls automatic behaviours necessary for survival
A pathway for axons between higher and lower brain centres
Associated with ten out of twelve pairs of cranial nerves

Divided into three parts:
Midbrain
Pons
Medulla oblongata

Question 21

Midbrain function

Answer 21

Reflex center for head and eye movements in response to sight and sounds

Question 22

Pons function

Answer 22

Bulging brain stem region between the midbrain and the medulla oblongata
Also forms bridge between cerebellum and brain stem
All sensory and motor fibers pass through the pons
Helps to regulate breathing

Question 23

Medulla Oblongata function

Answer 23

Most inferior part of the brain stem
Crossover of motor fibresoccurs here (i.e., damage to the left motor nerves causes right-sided paralysis)

Cardiac center –regulates heart rate
Respiratory center –regulates rate and depth of breathing
Vasomotor center –regulates blood pressure
Also regulates swallowing, sneezing, and vomiting

Question 24

Cerebellum function

Answer 24

Provides precise timing and appropriate patterns of skeletal muscle contraction (coordination –smooth movements)
Maintains posture
Maintains equilibrium using sensory input from inner ear (balance)

Question 25

Cranial Nerves - what is involved?

Answer 25

12 pairs of nerves that emerge from the brain:
10 pairs from the brain stem
1 pair from the cerebrum
1 pair from the thalamus

Types:
3 pairs are sensory nerves (sight, smell, sound)
5 pairs are motor nerves (signals sent to skeletal muscles)
4 pairs are mixed (both sensory and motor)

Question 26

Spinal cord functions

Answer 26

1.
Carries information
Sensory impulses from periphery to brain
Motor impulses from brain to periphery
2.
Integrating reflexes
Reflex centres (for a faster response for a particular stimulus)
Passes a nerve impulse from a sensory neuron to a motor neuron (instead of going up to the brain and back down)

Question 27

Primary somatosensory cortex

Answer 27

It processes afferent somatosensory input and contributes to the integration of sensory and motor signals necessary for skill movement

Question 28

Primary motor cortex function

Answer 28

Area that provides the most important signals for the production of skilled movement.

Question 29

Striatum function

Answer 29

The input module to the basal ganglia, a neuronal circuit necessary for voluntary movement control.. And memory control

Question 30

Globes pallidus function

Answer 30

Component of the basal ganglia it is meant to control conscious and propioceptive movements.

Question 31

Substantia Nigra pars reticulata

Answer 31

an output conveying signals from the basal ganglia to other brain structures

Question 32

SubsTANTIA nigra pars compacta

Answer 32

An input to the basal ganglia circuit supplying the striatum with dopamine.

Question 33

Superior colliculus (tectum) function

Answer 33

Incoperate environmental stimuli and coordination in gaze shifting both eyes and head movement

Question 34

Trigeminal nerve function

Answer 34

Provide sensory innervation to the face and is divided into 3 branches. Located in the pons. Sensory + motor nerve

Question 35

Facial nerve function

Answer 35

The flu it on is responsible for facial expressions, parasympathetic innervation of glands of the oral cavity and the lacrimal gland and sensory innervation of the anterior 2/3rd of the tongue.

Question 36

Glossopharyngeal function

Answer 36

It provides motor parasympathetic and sensory information to your mouth and throat. Sensory and motor impulses.

Question 37

Vagus nerve function

Answer 37

The vagus nerve of the regulation of internal organ functions, such as digestion, heart rate and respiratory rate as well as vasomotor activity and certain reflex actions such as a coughing, sneezing, swallowing and vomiting.

It is a mixed nerve.

Question 38

Spinal accessory nerve function

Answer 38

It is essential for neck and shoulder movement, the intrinsic musculature of the larynx, and the sensitive afferences of the trapezius and the sternocleidomastoid musculature.

Question 39

The hypoglossal nerve

Answer 39

Mainly and efferent nerve for the tongue musculature - controls the tongue. It is a motor nerve.

Question 40

Anterior horn of the spinal cord function

Answer 40

It sends out motor signals to the skeletal muscles.

Question 41

Posterior horn of the spinal cord function

Answer 41

Responsible for receiving the incoming afferent sensory signals. Includes light, proprioception and vibrations,

Question 42

Lateral horn of the spinal cord function

Answer 42

It is the central component of the sympathetic division of the autonomic nervous system.

Question 43

Anterior column of the spinal cord function

Answer 43

Contains motor neurone that affect the skeletal muscles - info that regards touch and sensation.

Question 44

Posterior column of the spinal cord function

Answer 44

Carry information about tactical sensations and proprioceptions.

Question 45

Ascending tracts of the spinal cord function

Answer 45

Carries sensory information from the body like pain and up to the spinal cord to the brain.

Question 46

Descending tracts of the spinal cord function

Answer 46

Voluntary motor function, muscle tone, reflexes and equilibrium, visceral innervation and modulation of ascending sensory signals.

Question 47

Identify the categories, by location, of the 31 pairs of spinal nerves.

Answer 47

There are 31 pairs of spinal nerves, located at the cervical, thoracic, lumbar, sacral, and coccygeal levels: 8 pairs of cervical nerves (C1-C8). 12 pairs of thoracic nerves (T1-T12). 5 pairs of lumbar nerves (L1-L5)
5 pairs of sacral nerves (S1-S5). 1 pair of coccygeal nerves (CO1).

Question 48

Primary motor cortex to muscles

Answer 48

The corticospinal tract carries motor signals from the primary motor cortex in the brain, down the spinal cord, to the muscles of the trunk and limbs. Thus, this tract is involved in the voluntary movement of muscles of the body. (lower)

The corticobulbar tract is able to provide voluntary control of the muscles of the face, head and neck, as well as the muscles involved in swallowing, phonation and facial expression. More precisely, the motor component of the trigeminal nerve supplies muscles of mastication. The facial nerve supplies the muscles of facial expression. The glossopharyngeal nerve innervates the muscles of the pharynx and larynx. While the accessory nerve supplies the sternocleidomastoid and trapezius muscles. (upper)

General
(A) The motor cortex sends motor signals to the spinal cord neuronal network which sends its outputs to the muscles. The spinal cord combines motor signals with afferent feedback to generate the motorneuron outputs.

Question 49

Pathway of spinal nerve

Answer 49

The spinal nerve divides into two branches: a larger anterior or ventral ramus, and a smaller posterior or dorsal ramus. The anterior/ventral ramus innervates the skin and muscle on the anterior aspect of the trunk, while the posterior/dorsal ramus innervates the post-vertebral muscles and the skin of the back.
The nerve fibres supplying the upper limb are from the anterior rami, which have been redistributed within a network of nerves, called the nerve plexus. The anterior rami of the upper cervical spinal nerves form the cervical plexus (supplies the anterior neck). The lower cervical and first thoracic anterior rami form the brachial plexus (supplies upper limb). The lower lumbar and upper sacral anterior rami form the lumbosacral plexus (supplies lower limb). The thoracic anterior rami remain segmental becoming the intercostal nerves in the intercostal spaces.