Chapter 18: Structure And Function Of Nervous System Flashcards
What are the 2 main parts of the human nervous system
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.
What is the structure of the central nervous system
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.
Describe the structure of the spinal cord
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
What is the functions of the sensory root
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
What is the structure and function of the motor root
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
What is a reflex
It is a simple stereotyped response that follows immediately after a certain stimulus is received.
How is the brain protected
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
What is cerebrospinal fluid
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.
Describe what the cerebral cortex is
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.
Describe the brain hemisphere
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
What is contralateral control
The left hemisphere controls right side of body and right hemisphere controls left side of body.
What is ipsilateral control
Where parts of the body are controlled by the same side of the brain
What is the functions of the left hemisphere
Involved mainly with the logical organisation and analysis of info and processing info sequencially
Regards as the language or verbal hemisphere
What are the functions of the right hemisphere
Process info holistically and simultaneously
Considered to be more creative and concerned with spatial or non verbal ability
What is the functions of the occipital lobe
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
What are the functions of the parietal lobe
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
What are the functions of the temporal lobe
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.
What are the functions of the frontal lobe
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.
What are the major structures of the brain
Outer layer called the neocortex
The subcortex
The hind brain
The mid brain
The forebrain
Name the 3 main structure of the hindbrain
The medulla oblongata
Pons
Cerebellum
State the structure and function of the medulla oblongata
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.
What is the structure and function of the pons
Acts as bridge between the medulla and other brain structure which also regulates sleep and wakefulness.
What are the functions of the cerebellum
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.
State the structure and function of the midbrain
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
State the structure and function of the forebrain
The major structures are thalamus
Hypothalamus
Basal ganglia
Limbic system
What is the structure and function of the thalamus
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
State the structure and function of the hypothalamus
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
State the structure and function of the basal ganglia
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
What is the structure and function of the limbic system
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.
What are the principles of brain functioning
Hierarchical functioning
Speficity and plasticity
Lateralization of functions
What is hierarchical function
More complex or higher structure control lower ones
The functions of structures higher up the hierarchy are more complex than those lower down
What is specificity and plasticity
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
What is the lateralization of functions
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.
What is the somatic nervous system
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)
What is the autonomic nervous system
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.
What is the functions of the sympathetic nervous system
Prepares the body for action by activating processes to release energy from the body.
What is the functions of the parasympathetic nervous system
Activates processes to restore the body’s functioning again and build up the body’s reserves
