Central nervous system Term 1 Flashcards
Describe CNS and function
Functions to maintain homeostasis and communicates via electrical impulses propagated in nerve cells(neurons), processing incoming messages and initiating outgoing messages.
Describe division of CNS vs PNS
CNS= axial brain or spinal cord and has neurons that mainly act as communicator links
PNS=made up of cranial and spinal nerves connect CNS with receptors, muscles, glands acting as receivers/effectors of message
Difference between CNS and Endocrine system
endo: chem messengers to communicate, less specific, longer lasting stimulation due to hormones
CNS: chem messengers and neurotransmitters, specific, shorter stimulation due to nervous impulses
Describe how the central nervous system is protected. Brief description for each
bone:
cranium: skull case surrounding brain
vertebral canal: surrounding spinal cord
bone tissue: dense, hard material that protects nervous tissue making up brain/spinal cord
meninges: Pia mater, Arachnoid, Dura mater
cerebrospinal fluid: shock absorber
Describe the protective role played the meninges
Pia mater:(inner layer) soft, delicate and contains more blood vessels to nourish tissue and helps maintain brain shape
Arachnoid:(middle layer) loose mesh, collagen fibres (web) contain cerebrospinal fluid
Dura mater: (outer layer)tough, fibrous, durable and helps protect brain due to rubber texture
Describe the protective role played the cerebrospinal fluid x3
Describe the formation and composition.
protection: shock absorber, cushioning blows or shocks to CNS
support: brain suspended inside cranium floating in surrounding fluid
transport: CSF formed from blood and circulates through CNS before re-entrance to capillaries, During this, it takes nutrients to cells of brain and spinal cord and carries away waste
Describe cerebrum structure and function
Largest part of brain
Made up of:
-grey matter (cerebral cortex)
-white matter
-basal ganglia (additional grey matter)
initiates and coordinates movement, regulates temperature, and enable memory, speech, intelligence
Define structure of cerebral cortex and function
Highly convoluted, outer layer of cerebrum
-allow a large SA of brain to fit inside skulls= increase efficiency
-contains 70% of all CNS neurons
-high order functions=thinking, reasoning, memory, learning, conscious awareness of surroundings
How are convolutions of cerebral cortex separated
Gyri (folded ridges) has shallow downfolds called sulci or deep downfolds called fissures
Deepest fissure is the longitudinal fissure separating brains two hemispheres
Define basal ganglia and function
Masses of grey matter within each cerebral hemisphere associated with control of skeletal muscles
Difference between white and grey matter of the brain
White: (inside)
-made up of myelinated axons
Grey: (outside)
-unmyelinated axons, neuron cell bodies and dendrites
Define myelin/myelin sheath and function
fatty sheath made by Schwann cells that wrap around the axon of most neurons
speeds up nerve transmission, acts as insulator and protects nerve fibres
Name the major lobes of each hemisphere of the cerebrum
frontal, temporal, parietal, occipital
Define node of Ranvier and function
microscopic gaps found in myelin sheath-speed up nerve impulses
Define frontal lobe location and function
label on a diagram
above temporal and next to parietal
-higher level executive function including speech/language, voluntary movement, problem solving, etc.
Define temporal lobe location and function
label on a diagram
below frontal and parietal above cerebellum
-memory, auditory processing i.e. comprehension
Define parietal lobe location and function
label on a diagram
touch, pressure, pain, temperature
Define occipital lobe location and function
label on a diagram
above cerebellum=vision
What are the three functional areas of cerebral cortex and there function
SAM
sensory- interpret impulses from receptors
association- emotions/intellect
motor-control muscular movement
Distinguish between bundles of nerve fibres in/out side of CNS
What are the three versions of tracts
in=tracts
-tracts that connect various areas of cortex w/in same hemisphere
-carry impulses between left and right hemisphere
-connect the cortex to other parts of brain/spinal cord
out=nerves
Describe the location and the role of the corpus callosum
label on a diagram
Wideband of nerve fibres at base of longitudinal fissure that link two cerebral hemispheres
Outline/Describe the structure and functions of the cerebellum
label on a diagram
Surface folded into series of parallel ridges (outer is grey matter inner is white)
-subconscious control of posture, balance and fine coordination of voluntary muscle movement
-neurons indirectly connected to almost all sensory systems e.g. ear for posture/balance
movements do not originate here so movement without it is possible but would not be controlled
Outline the structures and functions of the hypothalamus
label on a diagram i.e. specific areas in which it effects due to it’s main functions
maintaining constant internal environment (homeostasis)
regulates:
-ANS (autonomic nervous system): including heart rate, blood pressure, digestive juice excretion
-body temperature
-food/water intake
-sleep patterns
-bladder contractions
-emotional response
-hormone secretion/endo system coordination
Define medulla oblongata and function
label on a diagram
continuation of spinal cord allowing passage of many nerve fibres
-automatically adjusting body functions
under influence of hypothalamus, regulates:
-Cardiac centre: rate/force of heart beat
-Respiratory centre: rate/depth of breath
-Vasomotor centre: diameter of blood vessels
Outline the structure and function of the spinal cord .
Extends from foramen magnum to waist
grey matter
-canal running through middle of grey (contains cerebrospinal fluid)
white outer
-myelinated nerve fibres arranged in bundles=tracts=ascending and descending tracts
regulates: transmit nervous impulses toward/away from brain to/away
from muscles/glands and coordinates spinal reflexs
List ways in which the spinal cord is protected
vertebral column:
-ring of bone
meninges
-dura matter not attached directly to bone
-padding due to fat and connective tissue between dura and bone
Define ascending tract of white matter of spinal cord
sensory axons
-carry impulses from neurons upwards toward brain
-dorsal root and ganglion on nerve cell bodies outside CNS cell bodies
Define descending tract
motor axons
-conduct impulses downwards, away from brain
-ventral root with no ganglion
Define thalamus and function
sensory coordinator of brain
-receives and process information from sense before sending to cerebral cortex
