Lec 1: CNS Flashcards
What does the CNS consist of?
What are it’s responsibilities?
Brain & spinal cord
managing sensory data and motor commands
What is the role of visceral sensory receptors?
monitor internal organs
What is the role of somatic sensory receptors?
provide position, touch, pressure, pain, and temperature sensations
What is the role of special sensory receptors?
provide sensations of smell, taste, vision, balance, and hearing
what does the sensory division of the peripheral nervous system (PNS) do?
brings information to the CNS from receptors in peripheral tissues and organs
Define the peripheral nervous system
all neural tissue outside the CNS
what does the somatic nervous system (SNS) control?
skeletal muscle contractions
what clear, colorless substance surrounds the brain?
Cerebrospinal fluid (CSF)
what is the function of CSF?
acts as a cushion and acts as the brain’s lymphatic system
how do immune cells enter CSF?
the Choroid Plexus
where does the CSF reside?
in the subarachnoid space
Underneath the skull, we have 3 layers of the brain, list them in order of going further into brain (DAP)
dura mater
arachnoid mater
pia mater
what procedure can be performed if there is a suspected dysfunction in the CSF?
lumbar puncture (spinal tap)
where on the spine do we inject the needle to collect CSF?
between L3 and L4 from the thecal sac
what are the functions of the forebrain? what is it associated with?
it is associated with the highest level intellectual functions such as thinking, planning, problem solving, and speech
T/F not every person has the corpus callosum
True
what is the largest part of the brain called?
Cerebrum
what is the outer layer of the cerebrum called?
cerebral cortex
the cerebral cortex is divided into four sections, what are they? (FPOT)
Frontal lobe, parietal lobe, occipital lobe, and temporal lobe
what are the main function(s) of the frontal lobe? (DAPPy duck)
attention, planning, decision-making, personality
what are the main function(s) of the parietal lobe?
Integrates information from the senses (speech, taste, reading…)
what are the main function(s) of the occipital lobe?
Vision
what are the main function(s) of the temporal lobe? (ELM St)
Emotion, language, memory from smell and hearing
what does the Amygdala do?
governs emotions, self preservation
what does hippocampal formation do?
forms new memories
what two structures make up the diencephalon?
thalamus and hypothalamus
what does the thalamus do?
acts as a relay station for almost all sensory information coming from the periphery to the brain, regulates higher brain centers
what does the hypothalamus do?
main region for internal regulatory systems, stress reactions, emotion and motivation
the hypothalamus receives information from the __________ and regulates:
autonomic nervous system
body temp, sleep, circadian and sexual cycles
the hypothalamus sends hormonal signals to the rest of the body via?
the pituitary gland
describe the function of the midbrain
coordinates visual and auditory input from sense organs (such as eye movements, blinking, triggers startle reflex to sounds), helps control unwanted movements
what three structures comprise the hindbrain?
medulla, pons, and hindbrain
what does the medulla do?
controls heart rate, respiration and blood pressure, and swallowing
what does the pons do?
co-ordinates breathing and posture, receives info and decides where to send it
controls sleep, awakening cycles, and dream impulses
what does the hindbrain do?
controls body temp, simple reflexes (like coughing and sneezing) and digestion
what is the second largest part of the brain called?
the cerebellum
what does the cerebellum do?
-coordinates and integrates voluntary movement, posture, balance resulting in fluid motion
-spatial and temporal perception, adaptation to unexpected things
-disturbances: balance, speech, motor coordination, fine motor coordination
what is the role of the spinal cord?
receive sensory info from, and sends motor info to body
role of nociceptors
detect pain
role of mecanoreceptors
detect pressure, touch, movement, vibration, tension
role of proprioceptors
“receptors for self”, continuous info about body position and limbs in space
which specialized receptor is a major site for opioid receptors?
nociceptors
entry into the brain is inhibited by two barriers, what are they?
-physical barrier composed of endothelial cells with tight junctions
-active efflux pumps in endothelial cells, known as ATP binding cassette (ABC) transporters
the paracellular aqueous pathway for entry into brain transports?
water-soluble agents through tight junctions
the transcellular lipophilic pathway for entry into brain transports?
lipid-soluble agents through endothelium
transport protein entry into brain transports?
glucose, amino acids, nucleosides through endotheluim
the receptor-mediated transcytosis for entry into brain transports?
insulin, transferrin through endothelium
the adsorptive transcytosis for entry into brain transports?
albumin and other plasma proteins through endothelium
glia are support cells for neurons, what are the four main types?
astrocytes, oligodendrocytes, microglia (immune cell), and ependymal cells (epithelial cells that line ventricles)
T/F both oligodendrocytes and astrocytes help form the BBB
False, only astrocytes
what is an important function of oligodendrocytes within the CNS in regards to axons?
they wrap myelin sheaths around axons
where doe neurons communicate with each other?
at synapses
some neurotransmitters (NTs) are excitatory (+) and bind at synapses on postsynaptic cells, what is their function?
to create an action potential
what role do myelin sheaths play that surround axons?
they increase the speed of transmission of action potentials
what voltage is considered “at rest” in the axon?
-70 mV
what voltage is considered the threshold at which an action potential is triggered?
-55 mV
Explain step-by-step the occurrence of an action potential
- A stimulus triggers an increased voltage
- Depolarization occurs once the threshold is reached causing Na+ ions to flow into axon
- Repolarization occurs causing K+ ions to flow out of axon
- Hyperpolarization occurs to increase the voltage back to resting state
explain the divergent pathway of neurons (diversify)
one presynaptic neuron branches to affect a larger number of postsynaptic neurons
explain the convergent pathway of neurons (simplify)
many presynaptic neurons converge to influence a small number of postsynaptic neurons
what is usually required to trigger an action potential?
1000s of synapses
what do inhibitory postsynaptic potentials do?
decrease the likelihood or prevent an excitatory postsynaptic potential from reaching threshold
