CNS - Lecture 1 Flashcards
The central nervous system comprises of
The brain and spinal cord
3 main components of the brain:
cerebrum, cerebellum and brainstem
corpus callosum
nerve axons that link the right and left hemispheres of the cerebrum, so the 2 halves may communicate
cerebral cortex
outer layer of gray matter of cerebrum
4 lobes that make up the cerebral cortex (each hemisphere has these 4 lobes)
frontal, parietal, occipital and temporal lobe
parietal lobe functions
mediates skin and muscle sensation
frontal lobe functions
personality, emotions, control of movement
occipital lobe functions
vision
temporal lobe functions
hearing and memory functions
the forebrain comprises of the
cerebrum and diencephalon
Cerebellum location and function
located at the base of cerebrum; controls balance and voluntary movement (may have cognitive functions as well)
Brainstem is composed of:
- composed of the midbrain, pons, medulla oblongata
Brainstem functions
- supplys neurotransmitters to different parts of the brain
- control of the respiratory and cardiovascular muscles
- controls transmission in sensory, motor, reflex and pain pathways
- Initiation of locomotion
Basal ganglia functions
movement initiation, inhibition of muscles antagonistic to the desired movement
Thalamus functions
selects and relays sensory signals to cortex
Hypothalamus functions
homeostasis, emotions (head ganglia of the ANS)
spinal cord function
locomotor pattern generator
What is the meninges
membranes that cover the brain and spinal cord
what are the 3 layers of the meninges
- dura mater: tough outer layer
- arachnoid mater: spidery middle mesh
- pia mater: delicate inner layer
Meningitis is
infection of the meninges
Where is cerebrospinal fluid produced
in brain ventricles
What does the cerebrospinal fluid do
- maintains electrolyte balance around neurons
- bathe and support neural tissue
where does the cerebrospinal fluid go after being produced
reabsorbed into the blood in the veins at the same rate as it is produced
What are the 4 types of glial cells
Astrocytes
Oligodendrocytes
Ependymal cells
Microglia
Astrocytes
- form a scaffold that holds neurons together
- forms the blood-brain barrier
- forms scar tissue which inhibits regeneration of axons
- recycles neurotransmitter molecules
- maintains electrolyte balance
Oligodendrocytes
forms the myelin sheath around neuronal axons
Ependymal cells
produce cerebrospinal fluid
microglia
ingest bacteria and cellular debris
Gliomas is
A brain tumour arising from glial cells
Meningioma is
A brain tumour arising in the meninges
How is glucose transported from the capillaries to the neurons?
Carrier-mediated transport systems
capillaries of the BBB are tightly joined and therefor can protect..
neurons from chemical fluctuations and large molecules
Afferent
sensory input signals sent to CNS by sensory afferent nerve axons of the peripheral nervous system
Efferent
motor commands sent from CNS to muscles & glands by efferent (motor) axons
Vertebra column
boney structure that supports the trunk and the head on the legs; within the vertebrae is the spinal canal where the spinal cord is found
What does the spinal cord do
conveys signals from sensory receptors to the brain, as well as signals from the brain to effector organs
How many pairs of spinal nerves convey signals to and from the spinal cord?
31 pairs
Each spinal nerve innervates a specific area of the skin called a __________ and a specific set of muscles called a __________
dermatome
myotome
Posterior or dorsal means
towards back of body
Anterior or ventral means
towards the front of the body
Dorsal root ganglion (posterior root ganglion) is
A cluster of neurons in a dorsal root of a spinal nerve
Sensory afferent axons enter the spinal cord through the
dorsal roots
sensory afferent axons bifurcate meaning..
they split into ascending (carry info to the brainstem) and descending (travel caudally, towards the tail) axons
Motor neurons are located in the
ventral horn
Efferent axons of the motorneurons leave the spinal cord through the _______ _______ to innervate the muscles
ventral roots
what is central grey matter comprised of
motorneurons, interneurons, dendrites and axons
what is surrounding white matter comprised of?
bundles of axons (called tracts), which convey sensory signals and motor commands
The tracts (bundles of axons) are responsible for carrying
motor and sensory stimuli to and from the periphery
Cervical nerves mediate sensory input from
from the arms
thoracic nerves mediate sensory information from
the abdomen (trunk)
Lumbar, sacral and coccygeal nerves mediate sensory information from
the legs and feet
