Chapter 4 - Central Nervous System Flashcards
What is the nervous system?
A communication network and control centre of the body and is made up of the brain, spinal cord and nerve.
What is the basic stricture of the nervous system?
- The central nervous system (CNS)
- consist of the brain and spinal cord - The peripheral nervous system (PNS)
- made up of nerves that connect the CNS with the RECEPTORS, MUSCLES, AND GLANDS
these all work together in a coordinated way.
What is the main job of the CNS?
The central nervous system is where incoming messages and processed and outgoing messages are initated.
Why should the CNS be protected?
The brain and spinal cord are very delicate and vital parts of the body. Therefore it is important that they are protected.
What three things protect the CNS?
- BONES - cranium and vertebrae
- Membranes called MENINGES
- CEREBROSPINAL FLUID
+ A CAVITY OF SPACE
How does the Cranium protect the brain?
It is the OUTERMOST PROTECTIVE LAYER OF THE BRAIN IS THE CRANIUM.
The cranium protects the brain by housing it in its STRONG, RIGID, AND HARD bone structure.
How does the Vertebrae protect the spinal cord?
The spinal cord runs the vertebral canal - an opening in the vertebrae.
THESE BONES PROVIDE A STRONG, RIGID STRUCTURE TO PROTECT THE STRUCTURES UNDERNEATH.
What are Meninges? and their location.
Meninges are the 3 layers of connective tissue forming into membranes covering the spinal cord and brain.
Located: Inside the bones covering the surface of the brain and the spinal cord (i.e CNS)
List the three layers of Meninges.
- Dura mater
- Arachnoid mater
- Pia mater
What is the Dura Mater?
- the outer meningeal layer
- tough and fibrous providing a LAYER OF PROTECTION for the brain
- STICKS CLOSELY to the BONES OF THE SKULL but on the INSIDE of the VERTEBRAL CANAL, it is NOT SO CLOSE FITTING.
- OUTER MEMBRANE has been DESCRIBED as having a TEXTURE AND THICKNESS SIMILAR to a HOUSEHOLD RUBBER GLOVE.
What is the Arachnoid mater?
Middle meningeal layer
- LOOSE MESH OF FIBRES
What is the Pia mater?
The INNER meningeal layer
- More DELICATE
- Contains many BLOOD VESSELS and STICKS CLOSELY to the SURFACE OF THE BRAIN AND SPINAL CORD.
What is the Cerebrospinal fluid? AND WHERE IS IT FOUND?
CSF is the third protective structure
- IS A CLEAR, WATERY FLUID CONTAINING FEW CELLS AND SOME
- GLUCOSE, PROTEIN, UREA AND SALTS
- OCCUPIES a SPACE BETWEEN THE MIDDLE AND INNER LAYERS OF THE MENINGES.
- CIRCULATES THROUGH CAVITIES IN THE BRAIN AND THROUGH A CANAL IN THE CENTRE OF THE SPINAL CORD.
has 3 functions
What are the three functions of the CSF?
- PROTECTION:
- acts as a shock absorber, cushioning any blows or shocks to the CNS may sustain - SUPPORT:
- the brain is suspended inside the cranium and floats in the fluid that surrounds it - TRANSPORT:
- the CSF is FORMED FROM BLOOD and CIRCULATES AROUND and THROUGH the CNS before RE-ENTERING the blood CAPILLARIES.
- DURING its CIRCULATION it TAKES NUTRIENTS TO the CELLS of the BRAIN and SPINAL CORD and CARRIES AWAY their WASTES
What is the brain?
Complex organ - in structure and function.
Works as an integrated whole.
not completely discovered: is still a mystery and discoveries still happening today
List the major regions of the brain which major functions
- Cerebrum
- Corpus Callosum
- Cerebellum
- Hypothalamus
- Medulla Oblongata
What is the Cerebrum? STRUCTURE
- the biggest part of the brain
- outer surface area of 2-4mm thick of grey matter known as the CEREBRAL CORTEX
- GREY MATTER CONSISTS OF NEURON CELL BODIES, DENDRITES, AND UNMYELINATED AXONS.
BELOW THE CORTEX is WHITE MATTER, which is made up of MYELINATED AXONS.
DEEP INSIDE THE CEREBRUM IS ADDITIONAL GREY MATTER CALLED THE BASAL GANGLIA.
WHITE MATTER VS. GREY MATTER
WHITE MATTER = the part of the brain and spinal cord made up of myelinated fibers.
- the fatty nature of the myelin gives the white matter its colour and texture
GREY MATTER= the part of the brain and spinal cord made up of nerve cell bodies and unmyelinated fibres
What is the basal ganglia?
The masses of grey matter inside each cerebral hemisphere
Explain the structure of the Cerebral cortex
- is folded in patterns that greatly increase the surface area.
- in this way the cortex 70% of all neurons in the central nervous system
- folding produced rounded ridges called CONVOLUTIONS (varying from person to person)
- the convolutions are separated by either SHALLOW DOWNFOLDS CALLED SULCI OR DEEP DOWNFOLDS CALLED FISSURES.
What are convolutions?
an UPWARD FOLD of the cerebral cortex of the brain
aka - gyrus
What are Sulci?
SHALLOW DOWNFOLDS between the convolutions of the cerebral cortex
singular sulcus
What are fissures?
A DEEP DOWNFOLD in the cerebral cortex of the brain
What is the cerebral hemisphere?
One of the 2 halves of the cerebrum
What is the longitudinal fissure? what joins it?
The longest fissure in the human brain:
- almost separates the cerebrum into 2 halves
- considered a fifth lobe of each cerebral hemisphere
joining the 2 hemispheres, at the base of the longitudinal fissure is an area of white matter consisting of a large bundle of transverse fibres known as the corpus callosum.
Certain fissures and sulci are constant and are used to further subdivide each cerebral hemisphere into 4 lobes.
What are the four lobes?
- Frontal lobe
- Parietal lobe
- Temporal lobe
- Occipital
*5. Insula
Certain fissures and sulci are constant and are used to further subdivide each cerebral hemisphere into 4 lobes.
What is the insula? and where is it located?
Part of the cerebrum, deep inside the brain and is regarded as a fifth lobe.
function: recognition of different senses and emotions, addiction and psychiatric disorders
What is the function of the frontal lobe?
Thinking, problem-solving, emotions, personality, language, and control of movement.