Nervous System - Organization Flashcards
describe main divisions of nervous system, compare CNS and PNS, explain meninges and circulation of CSF, identify steps in forming a response to environmental challenges
sensory input
- sensory receptors detect change
2. electric signals (nerve impulses) are transmitted to brain
where does signal integration occur?
CNS
motor output
- electric signals (nerve impulses) are transmitted from the brain
- brain sends signals to effector organ
main divisions of nervous system
- central nervous system
- peripheral nervous system
CNS
- brain
- spinal cord
PNS
- cranial nerves (12 pairs)
- spinal nerves (31 pairs)
nerves
- bundles of cytoplasmic extensions of the nerve cells (neurons)
- specialized cells that carry messages from one part of the body to another
ganglia
bundles of nerve cell bodies
3 parts of neuron
- soma: cell body
- dendrites: processes that gather info
- axons: process that conveys info
afferents
- carry signals towards CNS
- sensory
efferents
- carry signals away from CNS
- motor
somatic nervous system
- voluntary
- related to skeletal muscles
autonomic nervous system
- involuntary
- related to visceral organs
parts of the autonomic nervous system
- sympathetic
- parasympathetic
- enteric
cerebrum surface components
- gyri - convolutions
- sulci - grooves
- fissures - deep and long sulci
lobes of the cerebrum (5)
- frontal lobe
- parietal lobe
- occipital lobe
- temporal lobe
- insula
frontal lobe
motor
cerebrum
broca’s area
- responsible for speech production
- damage results in “expressive aphasia”
parietal lobe
sensory
- location of body parts
- interpreting visuals
(cerebrum)
occipital lobe
vision
cerebrum
temporal lobe
hearing
cerebrum
wernicke’s area
- responsible for understanding speech
- damage results in “receptive aphasia”
insula (island of reil)
- olfacto-gustatory (smell/taste)
cerebrum
parts of the diencephalon (3)
- thalamus
- hypothalamus
- epithalamus (pineal gland)
thalamus
- relay station for info going both ways
- “relay sensory and motor signals to the cerebral cortex
(diencephalon)
hypothalamus
- key role in maintaining homeostasis
- control centre of autonomic nervous system
- link between nervous system and endocrine system
(diencephalon)
epithalamus (pineal gland)
control centre for circadian rhythm
diencephalon
where is the diencephalon
centrally located, surrounded by cerebral hemispheres
parts of the brain stem (3)
- midbrain
- pons
- medulla oblongata
midbrain
motor, visual, and auditory information
brain stem
pons
- breathing, swallowing, taste, facial expression, posture
- communication between different parts of the brain
(brain stem)
medulla oblongata
- cardiac, respiratory, and vasomotor functions
- “helps regulate breathing, heart, and blood vessel functions”
- decussation occurs here
(midbrain)
decussation
- crossover of nerve fibres
cerebellum
- functions as motor area
- mediates contractions of skeletal muscles (voluntary/involuntary)
- responsible for balance, coordination, and posture
- enables precise and accurate movements
what is the limbic system involved in
- emotional responses and socio-sexual behaviours (need to survive)
- motivation and memory formation (several parts)
parts involved in motivation and memory formation in the limbic system (4)
- hippocampus
- amygdala
- cingulate gyrus
- corpus callosum
hippocampus
forming memory
limbic system
amygdala
aggression centre
limbic system
cingulate gyrus
emotions, behaviour
limbic system
corpus callosum
info transfer between the two hemispheres
limbic system
grey matter (brain)
- outer part of cerebral cortex
- lots of neuronal bodies
white matter (brain)
- inner part of cerebral cortex
- lots of axons
basal ganglia
- located deep beneath cerebral cortex
- assist in movement by suppressing unwanted movement
types of fibres in white matter
- association fibers
- commissural fibers
- projection fibers
association fibers
transmit impulses from one gyrus to another (in same hemisphere)
commissural fibers
transmit impulses from one cerebral hemisphere to the other
“commute”
projection fibers
- ascending and descending
- transmit impulses to and from cerebrum (to and from spinal cord)
tracts
collections of axons travelling together in the CNS
nuclei
collections of neuron cell bodies in the CNS
meninges
- three layers of protective tissues
- surround the brain and spinal cord
parts of meninges
- dura mater (outer)
- arachnoid (middle)
- subarachnoid space
- pia mater (innermost)
subarachnoid space
filled with CSF
ventricles
fluid-filled cavities found in the brain
choroid plexuses
specialized capillary structures that produce CSF
CSF volumes
- ventricles: 35mL
- spinal cord: 100mL
CSF formed per day
500mL
CSF vs plasma
wayyy less protein!
Blood Brain Barrier
- lack of direct access of blood-borne substances to the brain’s interstitial fluid
- barrier between arterial blood and extracellular fluid compartment
- “filtering mechanism of capillaries that carry blood to the brain and spinal cord tissue, blocking passage of certain substances”
functions of CSF (4)
- cushions brain against mechanical shock
- carries nutrients to brain cells
- transports waste products away from brain cells
- supports nervous tissues
lumbar puncture (spinal tap)
needle inserted between 3rd and 4th lumbar vertebrate
(spinal cord thinnest here, so less chance of damaging it)
cranial nerves
- originate from brain stem
- perform basic functions of the head and neck
spinal nerves
- originate from spinal cord
- perform basic functions for the limbs and the trunk
types of brain behaviours
- motor behaviours (actions)
- affective behaviours (emotions)
- cognitive behaviour (thoughts)
neuroendocrine system control
- provides organ-wide control of physiological systems
- nervous system provides short-term and rapid control
- endocrine system provides long-term and steady control
