Structure of the Nervous System [W3] Flashcards
What is the CNS?
Central nervous system - brain and spinal cord
What is the PNS?
Parasympathetic nervous system - nerves that carry info around the body
What are the components of the PNS?
Somatic nervous system; autonomic nervous system (sympathetic division, parasympathetic division)
What is white matter?
myelinated axons
What is grey matter?
cell bodies and interneurons
What is the function of the autonomic nervous system?
Regulates body’s internal environment; more automatic processes, like heartbeat, organ function etc.
What is the function of the somatic nervous system?
Interacts with the external environment?
What is a bundle of axons called in the brain? In the body?
brain –> tract ; body –> nerve
function of the parasympathetic division of the ANS?
rest + digest
function of the sympathetic division of the ANS?
activation, fight/flight
What is processed in the grey matter of the spine? What is the function of the spine?
pattern generators (i.e., for walking), simple reflexes (i.e., pulling hand away from hot stove), and more complex reflexive movements; transmit information to/from brain
layers of protection around the brain (outside to inside)
skull; meninges (Dura mater, arachnoid layer, pia mater); subarachnoid space (filled with CSF); brain
def: Blood Brain Barrier
barrier to entry for substances to get to the brain; Capillaries in brain have tight junctions which prevents free movements of substances (esp. larger substances) in/out of blood
Brain folds – why?
more surface area
def: gyrus
bumps in the brain
def: sulcus
shallow grooves in the brain
function of cerebrospinal fluid
protects the brain by acting as a “cushion”; helps to remove waste products from brain to CNS functions properly
function of cerebrospinal fluid
protects the brain by acting as a “cushion”; helps to remove some waste products from brain; could be how some fluids get to the brain
4 lobes of the brain & approx. location
frontal (front); parietal (top, back section); occipital (back); temporal (sides – think ‘temples’)
4 lobes of the brain & approx. location
frontal (front); parietal (top, back section); occipital (back); temporal (sides – think ‘temples’)
“dorsal”
above (a.k.a. superior) [think: dorsal fin]
“ventral”
below (a.k.a. inferior) [think: toward belly]
“medial”
middle
“lateral”
side
“anterior”
front (a.k.a. rostral, frontal)
“posterior”
rear (a.k.a. caudal)
Where is the sagittal plane?
middle (on Y axis), running front to back
Where is the horizontal plane?
middle (on Y axis) running side to side
Where is the frontal plane?
middle (on X axis) running top to bottom
When does the nervous system start to develop?
3 weeks post conception
Describe how the brain is formed (brain devel.)
ovum and sperm combine to form zygote // Zygote divides to form 2, 4, 8, etc cells // cells become specialised // 3 weeks after conception, neural plate and stem cells are plentiful enough to form nervous system, neurons and glia // neural plate folds to form neural groove, which then fuses into neural tube // inside tube becomes the ventricles and spinal canal, filled with CSF // neural tube develops three chambers // neural tissue around 3 chambers become forebrain, midbrain, hindbrain
Direction of information in efferent nerve bundles?
efferent moves away from the brain [think: exist] and carries motor signals toward muscles
Direction of information in afferent nerve bundles
afferent moves toward brain and carries sensory signals from muscles to brain
What direction does information flow in the ANS?
both efferent and afferent signal flow, to and from CNS
What are the three protective membranes around the brain?
meninges [dura mater, arachnoid layer, pia mater]
Where are the blood vessels in the brain?
Main vessels are on the outside/brain surface; smaller vessels branch and go into the brain
head injury can cause _______ to swell
ventricles
What defines the boundaries of the four lobes in the brain?
the sulci and gyri in the cortex
What are the three chambers the neural tube develops into? (brain devel)
forebrain, midbrain, hindbrain
What does the forebrain develop into and how?
Folds back on itself to become the Cortex; and diencephalon (thalamus, hypothalamus)
midbrain becomes the _______
mesencephalon
hind brain develops into ______, ________, _______
pons, medulla, cerebellum
the forebrain, midbrain, and hindbrain make up the ___________
brainstem
Function of the medulla
essential life functions (i.e., breathing, heartbeat, etc.)
What is the pons
[means: “bridge”] the bump where fibres cross over from one side to the other; involved in sleep and arousal
def: reticular formation
loc. in the tegmentum, runs along brainstem; includes many nuclei, net-like/web-like structure; sections within the reticular formation are main producers of various neurotransmitters
function of the cerebellum
[means: little brain] responsible for coordination and movement, skilled motor control
def: raphe nucleus
nuclei in the pons, part of the reticular activating system; neurons produce 5HT/serotonin
What are the sites of significant ACh production in the midbrain?
pedunculopontine nucleus and laterodorsal tegmental nucleus