Chapter 18: Structure And Function Of Nervous System

Question 1

What are the 2 main parts of the human nervous system

Answer 1

The central nervous system which is made up of the brain and spinal cord that receives info from the outside world

The peripheral nervous system that made up of neurons and organs that lie outside the brain and spinal cord with two parts being the autonomic nervous system and the somatic nervous system.

Question 2

What is the structure of the central nervous system

Answer 2

The CNS are protected by bones like the skull and vertebrae for the brain and spinal cord respectedly. There are also 3 membranes the Dura mater which is strong and thick the middle arachnoid Which is thick but more flexible and the inner pia mater which is soft and flexible

The brain and spinal cord are made up of two relatively identical halves where nerve tract and structure found in one half will be found in the other.

Question 3

Describe the structure of the spinal cord

Answer 3

It extends from the brain down the length of the back protected by the bones that make up the spinal cord.

The spinal cord is made up of columns of white matter which are bundles of myelinated axons where these axons leave the spinal cord and form nerves.

There are 30 pairs of nerves on each side of spinal cord that divide into a motor and sensory root

Question 4

What is the functions of the sensory root

Answer 4

The sensory root consists of nerve fibres that convey sensory information to the brain which is received from the sensory receptors in the skin skeletal muscles tendons and joints and the internal organs of the body

The info is conducted from sensory receptors to the brain along the sensory root of the spinal nerve

Question 5

What is the structure and function of the motor root

Answer 5

The motor root consists of motor nerve fibres that convey info from the brain to the muscles and glands of the body

The spinal nerves carry sensory and motor messages to and from the spinal cord and keep the body in communication with the brain

Question 6

What is a reflex

Answer 6

It is a simple stereotyped response that follows immediately after a certain stimulus is received.

Question 7

How is the brain protected

Answer 7

The space between the skull and the brain is filled with cerebrospinal fluid which is produced by the brain and surrounds it to protect it from being bumped or injured

The brain is protected by the blood brain barrier that keeps out harmful substances through capillaries that are impermeable to certain substances

The brain is richly supplied with blood vessels that carry important substances like O2 and transport waste like CO2 from the brain cells

Question 8

What is cerebrospinal fluid

Answer 8

A clear bodily fluid in the form of a very pure saline solution with microglia that occupies the subarachnoid space in the brain (between the skull and the cerebral cortex), and which acts as a cushion or buffer for the cortex.

Question 9

Describe what the cerebral cortex is

Answer 9

It’s the outer layer of the brain.

It has a wrinkled appearance because the surface of the cortex is composed of tissue mainly made up of cell bodies that have a great colour called grey matter.

Question 10

Describe the brain hemisphere

Answer 10

Has the left and right hemisphere that is connected by the corpus callosum which is a thick band of fibres allowing communication between the two hemispheres

Question 11

What is contralateral control

Answer 11

The left hemisphere controls right side of body and right hemisphere controls left side of body.

Question 12

What is ipsilateral control

Answer 12

Where parts of the body are controlled by the same side of the brain

Question 13

What is the functions of the left hemisphere

Answer 13

Involved mainly with the logical organisation and analysis of info and processing info sequencially

Regards as the language or verbal hemisphere

Question 14

What are the functions of the right hemisphere

Answer 14

Process info holistically and simultaneously

Considered to be more creative and concerned with spatial or non verbal ability

Question 15

What is the functions of the occipital lobe

Answer 15

Lies at the back of the brain and are the primary visual areas of the cortex where visual input is interpreted.

Also responsible for combining visual stimuli into meaningful patterns.

The integration of sensory experience takes place in occipital lobe

Question 16

What are the functions of the parietal lobe

Answer 16

Made up of the somatosensory cortex which refers to bodily sensations like touch temperature pressure and pain.

The parietal lobe receives input about sensations and info from muscles and joints which tells the brain the position of the body in space

It puts together all the somatosensory info received and provide feedback based on the info helping the hands and feet coordinate body movement in space

Question 17

What are the functions of the temporal lobe

Answer 17

Perception of sound. Auditory info is projected to the temporal lobe where it’s registered and interpretated

It allows us to understand spoken language and other sounds

The left temporal lobe is regarded as language centre of the brain

The right temporal lobe is concerned with non verbal sound and plays a role in speech.

Question 18

What are the functions of the frontal lobe

Answer 18

Evolved part of the brain which regulates complex mental activity and behaviour

Main function is control of voluntary movement including production of speech

The motor area of frontal lobe ensure smooth performance of a sequence of motor skills that make up complex actions like talking

Other important functions are to maintain attention and concentration through optimal arousal of the cortex to apply abstract thinking reasoning and planning and regulate emotions and behaviour.

Question 19

What are the major structures of the brain

Answer 19

Outer layer called the neocortex

The subcortex

The hind brain
The mid brain
The forebrain

Question 20

Name the 3 main structure of the hindbrain

Answer 20

The medulla oblongata
Pons
Cerebellum

Question 21

State the structure and function of the medulla oblongata

Answer 21

Extension of spinal cord and consists of grey matter surrounded by white matter

Groups of neurons in medulla act as reflex centres for processes that ensure survival like breathing and heart rate

Two bumps called pyramids formed by the crossing of motor nerve tracts that maintain the brains contralateral control of muscles

Inside is a network of cell bodies called reticular formation which extends upward into the midbrain which stimulates the brain keeping it active and alert but also preventing it from overstimulation by regulating input and by do doing maintains an optimal arousal level so that the brain functions properly.

Question 22

What is the structure and function of the pons

Answer 22

Acts as bridge between the medulla and other brain structure which also regulates sleep and wakefulness.

Question 23

What are the functions of the cerebellum

Answer 23

Main function is to co ordinate motor movement by regulating posture balancing muscle tone and muscle co ordination

By integrating and comparing info received from body it allows the necessary adjustments to be made so that movements initiated by the brain are carried out in a co ordinated sequence.

Question 24

State the structure and function of the midbrain

Answer 24

Very small part of the brain and is a continuation of the pons which consists of the tectum and tegmentum

The tectum has the superior colliculus which is the reflex centre for vision and the inferior colliculus which is the reflex centre for hearing

The tegmentum is involved in the regulation of motor movement

Question 25

State the structure and function of the forebrain

Answer 25

The major structures are thalamus
Hypothalamus
Basal ganglia
Limbic system

Question 26

What is the structure and function of the thalamus

Answer 26

Consists of a collection of nerve nuclei and main function is to act as relay station for sensory info where sensory info received by thalamus and sent on to appropriate structures or area of the cortex for integration or interpretation of info

Question 27

State the structure and function of the hypothalamus

Answer 27

Lies below thalamus and has many nerve nuclei that are included in functions as

Maintaining the internal environment of the body like temperature water intake sexual activity heart beat blood pressure and digestion

State of sleep and wakefulness

Emotions

Question 28

State the structure and function of the basal ganglia

Answer 28

Consists of 3 large groups of neurons that regulate slow smooth movements like walking.

Axons from some of the neurons project to the motor areas of the cerebral cortex and midbrain

Question 29

What is the structure and function of the limbic system

Answer 29

Consists of the hippocampus, amygdala, septum, limbic cortex that regulate motivated behaviour emotions and memory

The limbic system evaluates experience as positive or negative links that info to memory and helps the person to adapt to similar situation that arise

The hippocampus plays an important role in memory by comparing new incoming memory with existing info in memory

The amygdala plays a role in the experience of fear and anger as well as relaxation and is linked to the emotional aspects of memories

The septum is regarded as the brains pleasure or rewards centre

The limbic cortex regulates the subcortical structures mentioned and plays s role in the regulation of emotion.

Question 30

What are the principles of brain functioning

Answer 30

Hierarchical functioning
Speficity and plasticity
Lateralization of functions

Question 31

What is hierarchical function

Answer 31

More complex or higher structure control lower ones

The functions of structures higher up the hierarchy are more complex than those lower down

Question 32

What is specificity and plasticity

Answer 32

Brain functioning is both specific and plastic meaning that certain structures may be connected in specific ways but the brain is also capable of plasticity are being changeable in that new connections can be formed in the brain

Question 33

What is the lateralization of functions

Answer 33

The location of functions more predominant in one hemisphere than the other

The higher up the hierarchy the structure is the more lateralized it’s function is likely to be.

Question 34

What is the somatic nervous system

Answer 34

Has a sensory and motor component

The somatic nervous system refers to the nerves that conduct info from the sensory receptors in the body to the CNS (afferent nerves) and from the CNS to the skeletal muscle in the body (efferent nerves)

Question 35

What is the autonomic nervous system

Answer 35

It controls the processes that regulate our internal organs and glands so that the body functions evenly

Contains the sympathetic and parasympathetic nervous system

These systems work opposite to each other.

Question 36

What is the functions of the sympathetic nervous system

Answer 36

Prepares the body for action by activating processes to release energy from the body.

Question 37

What is the functions of the parasympathetic nervous system

Answer 37

Activates processes to restore the body’s functioning again and build up the body’s reserves