bmsc midterm 2 cards

Question 1

the central nervous system

Answer 1

brain and spinal cord
seperated into gray matter a and white matter
gray consists: consists of unmyelinated somas, dendrites and axons,
white: mainly myelinated axons

Question 2

spinal cord

Answer 2

major pathways for information flowing back and forth between the brain and the skin, joints and muscles of the body
divided into 4 segments:
cervical (8)
thoracic (12)
lumbar (5)
sacral (5)
coccygeal (1)

Question 3

ascending tracts
descending tracts

Answer 3

ascending tracts: carry sensory information to the brain
dorsal and external lateral

descending tracts: carry commands to motor neurons
ventral and interior lateral

Question 4

spinal reflex

Answer 4

the spinal cord can act as the integrating center to initiate a response to a stimulus without receiving input from the brain

important in body movement

Question 5

brain

Answer 5

organ providing human species with its unique attributes

1400g, 1.4 kg, 85 billion neurons, many containing thousands of synapses

6 major divisions:
cerebrum
cerebellum
diencephalon
brainstem: midbrain, pons, medulla

Question 6

ultimate emergent property

Answer 6

the brain
the ultimate emergent property: how do chemical and electrical signals in neurons lead to complex behaviours?

individual neurons reductionist, then groups of neurons (circuits, pathways, networks) then complex behaviour

Question 7

brainstem

Answer 7

oldest region, 4 major regions
mid brain, pons, medulla, and recticular formation

ascending and descending tracts run through the brain stem

contain 11 of 12 cranial nerves: carry sensory and motor info for head and neck

contain many nuclei
involved in many basic processes in the body including arousal and sleep, muscle tone and stretch reflexes, coordination of breathing, blood pressure regulation and modulation of pain

Question 8

medulla (part of brainstem)

Answer 8

right at the junction of the spinal cord
white matter contain all ascending somatosensory tracts and descending corticospinal tracts

90% of corticospinal tracts decussate (crossover) at the pyramids
why the left side of brain controls the right body

nuclei in the medulla control many involuntary functions, including the cardiovascular center and the medullary respiratory center

contains the vomiting center
contains the deglutition center (swallowing)
caughing, sneezing, hiccuping

Question 9

nuclei and ganglia

Answer 9

nuclei: clusters of cell bodies in CNS
ganglia: clusters of cell bodies in PNS

Question 10

dorsal horn and ventral horn (grey matter)

Answer 10

parts of the gray matter
info comes out (efferent) the ventral root and within the horns there are nuceli

the ventral horn consists of somatic motor nuclei and autonomic efferent nuclei

dorsal horn consists of somatic sensory nuclei ( info from the skin to the brain)
viscreal sensory nuceli carrys info from internal organs than to the brain

Question 11

pons and midbrain

Answer 11

pons: contain nuceli and tracts
relays info between the cerebellum and cerebrum
assists the medulla in the coordination of breathing

midbrain (mesencephalon): junction between lower brainstem and diencephalon (nuclei and tracts)
primary function is controlling eye movement
also relay auditory and visual reflexes (movement of body in response to these stimuli)
contains the substania nigra

Question 12

reticular formation

Answer 12

extends throughout the brainstem: small clusters of neuronal cell bodies interspersed among tracts (ascending and descending)

important in consciousness, arousal, attention, and alertness

reticular activating system RAS inactivated during sleep, damage can induce coma

regulates muscle tone, assists in vital functions (HR,BP, resp rate)

Question 13

cerebellum

Answer 13

second largest brain structure
two cerebellar hemispheres

processes sensory info related to movement and coordinates the execution of movement

sends feedback signals to motor areas of the cerebral cortex, via its connections to the thalamus and pons helping to correct any erros and smooth the movements

main area regulating posture and balance

Question 14

diencephalon

Answer 14

lies between the brain stem and cerebrum

two primary structures: thalamus and hypothalamus
two endocrine structures: pineal gland and pituitary

Question 15

thalamus

Answer 15

part of the diencephalon
relay center: receives sensory info from optic tract, ears, spinal cord and relays it to relevant sensory areas in cortex
relays info from cerebellum to motor areas in cortex

Question 16

pineal gland

Answer 16

part of the diencephalon
cyclically releases melatonin involved in sleep/wake

Question 17

hypothalamus

Answer 17

part of the diencephalon
center for homeostasis
influences autonomic and endocrine function

functions: activates sympathetic nervous system
maintains body temp
controls body osmolarity
controls reproductive functions
controls food intake
influences behaviour/emotions
influences cardiovascular control

Question 18

pituitary gland

Answer 18

endocrine structure in the diencephalon

output of the hypothalamus

posterior pituitary is neural tissue, an extension of the brain that secretes neurohormones made in the hypothalamus

anterior pituitary is endocrine tissue
one hormone releases that is involved in a series of hormones

Question 19

cerebrum

Answer 19

largest part of the brain

gray matter includes the cerebral cortex, basal ganglia, and limbic system

white matter: tracts,
area of higher processing “seat of intelligence”

two hemispheres divided into 4 lobes, connected by corpus callosum
frontal lobe, pariental temporal, occipital

Question 20

basal nuclei (ganglia) should be nuclei but can be called ganglia

Answer 20

three nuclei collectively termed the basal ganglia (nuclei)
-globus pallidus, putamen, caudate nucleus

major job is regulating the initiation and termination of movement

receives input from cerebral cortex and provides output to motor portions of the cortex

Question 21

limbic system

Answer 21

“emotional brain” plays a role in a range of emotions, including pain, pleasure, anger, affection

also believed to play a primary role in learning and memory

3 major componetns: cingulate gyrus
amygdala (emotion)
hippocampus (memory)

Question 22

cerebral cortex

Answer 22

outermost layer of the cerebrum
integrating center for CNS

functionally divided into 3 specializations:
1)sensory areas (translate sensory input into perception)
2) motor areas (direct skeletal muscle movement)
3) association areas (integrate info from sensory and motor areas and help direct voluntary behaviours and deal with complex integrative functions)

Question 23

lobes

Answer 23

frontal lobe: primary motor cortex, motor association area (premotor cortex)

parietal lobe: primary somatic sensory cortex, sensory association areas

occipital lobe: vison,

temporal lobe: hearing, balance

Question 24

cerebral laterlization (dominance)

Answer 24

distribution of functional areas in the two hemispheres is not symmetrical

writing in the right hemisphere why your dominant in the right hemisphere
this is just avg not for sure

Question 25

sensory system purpose

Answer 25

provides infro about the environment inside and outside the body

Question 26

special senses vs somatic sense (both processed consciouslly)

Answer 26

specical:vision, hearing, taste, smell, equilbrium somatic: touch, temperature, pain, itch, proprioception

Question 27

somatic stimuli vs viscreal stimuli (both subconscious)

Answer 27

somatic: muscle length and tension, proprioception viscreal: blood pressure, distension of gastrointestinal tract, blood glucose concentration, internal body temp

Question 28

general properties of sensory systems

Answer 28

a sensory neuron with a transducer (receptor), that converts a physical stimulus into a intracellular signal (change in membrane potential), usually through the opening or closing of gated channels

Question 29

simple, complex, special sensory receptors

Answer 29

simple receptors: are neurons with free nerve endings. may have myelinated or unmyelinated complex neural receptors: have nerve endings enclosed in connective tissue capsules, touch/proprioception most special senses are cells that release neurotransmitter onto sensory neurons, initiating action potenitals.

Question 30

types of sensory receptors

Answer 30

chemoreceptors: oxygen, pH, various organic molecules such as glucose blood chemoreceptors, nociceptors, taste, smell mechanoreceptors: pressure (baroreceptors), cell stretch (osmoreceptors), vibration, sound touch, proprioceptors, auditory, balance photoreceptors: photons of light, vision (rodes and cones) thermoreceptors: varying degrees of heat, thermal receptors, nociceptors

Question 31

mechanically gated channels

Answer 31

coverts mechanical stimulus into electrical signal receptor potential aka generator potential (equivalent to graded potential)

Question 32

receptive fields

Answer 32

physical area where a sensory receptor can respond within sensory neurons are activated by stimuli and fall within the physical area size depends on the type of sensory receptor if there is convergence of multiple primary neurons onto a secondary neuron, meaning multiple primary will synapses on a secondary convergence creates a large receptive field small fields in sensitive areas

Question 33

CNS integrates sensory information

Answer 33

visceral sensory info is integrated in the brain stem and spinal cord almost all special and somatic sensory info routed through the thalamus thalamus directs it to the relevant cortical centers olfactory pathwyas from the nose project through the olfactory bulb to the olfactory cortex equilbrium pathways project primarily to the cerebellum

Question 34

special senses and somatic senses

Answer 34

special senses: have dedicated cortical regions somatic senses: integrated in the primary somatosensory cortex

Question 35

CNS distinguishes four properties of stimulus. this is how CNS detect one sensation from the other

Answer 35

1) modality- the physical stimuli being sensed, determined by the sensory receptor being activated, temperature vs touch receptor and where the pathways terminate in the brain 2)location 3)intensity 4)duration

Question 36

location of stimulus

Answer 36

coded according to which receptive fields are being activated Most sensory stimuli for specific regions of the body are projected to particular areas of the somatosensory cortex determined by where in teh cerebral cortex sensory info is projected to large regions of the cortex dedicated to large regions of the body such as touch

Question 37

intensity and duration of stimulus

Answer 37

because AP amplitude is constant, intensity cannot be determined by amplitude. intensity is determined by the number of receptors being activated (population coding) and the frequency of action potentials coming from those receptors (frequency coding) duration of stimulus is determined by how long APs are being activated

Question 38

duration also depends on receptor adaptation tonic vs phasic

Answer 38

tonic receptors: slowly adapting receptors that respond for the duration of a stimulus parameters that need to be constantly monitored phasic receptors: rapidly adapt to a constant stimulus and turn off respond of a change in parameter, stop once stimulus costant

Question 39

sensory pathway specificity

Answer 39

1) Each receptor is most sensitive to a particular type of stimulus 2) a stimulus above threshold initiates AP's in a sensory neuron that project to the CNS 3) stimulus intensity and duration are coded in the pattern of AP's reaching the CNS 4) stimulus location and modality are coded according to which receptors are activated or by the timing of receptor activation 5) each sensory pathway projects to a specific region of the cerebral cortex dedicated to a particular receptive field. the brain can then tell the origin of each incoming signal

Question 40

autonomic nervous system

Answer 40

involuntary control of smooth muscle, cardiac muscle, many glands and some adipose tissue subdivided: sympathetic (fight of flight) and parasympathetic (rest and digest) the autonomic nervous system works closely with the endocrine system and behavioural systems to maintain homeostasis

Question 41

autonomic pathways have two efferent neurons in series

Answer 41

1 preganglionic will synapse with 8 or 9 postganglionic neuron CNS---> preganglionic--> autonomic---> postganglionic----> target tissue (smooth muscle, gland etc)

Question 42

sympathetic (pre and post ganglionic)

Answer 42

ganglia are mainly found in two ganglion chains running along side vertebral column preganglionic neurons orginate in thoracic and lumbar regions short preganglionic, long post ganglionic neurons

Question 43

parasympathetic

Answer 43

preganglionic neurons orginate in the brainstem and exit via cranial nerves or from the sacral region of the spinal cord ganglia are mainly located on or near the target organs long preganglionic, short postganglionic neurons cranial nerve x (vagus) contains 75% of all parasympathetic neurons

Question 44

the autonomic nervous system uses a variety of chemical signals (aCH and norepinephrine)

Answer 44

preganglionic always uses acetlycholine (para and symp) onto nicotinic receptors postganglionic use nicotonic receptors (both in para and symp) nicotinic=ionotropic sympathetic pathways uses acetlycholine and norepinephrine most post ganglionic use norepinephrine onto muscarinic parasympathetic pathways uses just aCH meaning most of their post ganglionic receptors use acetlycholine onto muscarinic adrenergic and muscarinic are metabotropic

Question 45

the adrenal medulla secretes catecholamines

Answer 45

adrenal medulla is a specialized neuroendocrine structure associated with sympathetic nervous system often described as a modified sympathetic ganglion, contain chromaffin cells (modified ganglion cells no axons and release epinephrine) which are modified postganglionic neurons sits on top of the kidneys, it has 2 structures the adrenal cortex (true endocrine tissue) and adrenal medulla (neuroendocrine tissue)

Question 46

autonomic pathways (postganglionic)

Answer 46

target smooth and cardiac muscle, many exocrine glands, a few endorcrine glands, lymphoid tissue, liver and some adipose tissue autonomic varicosities has a whole bunch of terminals and receptors to cause a larger response in the target tissue receptors exist across the tissue not under the varicosities, neurotransmitters diffuse to receptors

Question 47

varicosities

Answer 47

AP would go through the axon of postganglionic than into the varicosities like axon terminals, they contain the enzymes necessary to create the neurotransmitters synethize/detachh them aCH nonpinphrine,

Question 48

neurotransmitters are synethesized in the axon/varicosities

Answer 48

travels down the axon into a bunch of varicosities 1) AP arrives at varicosity 2) depolarization opens voltaged gated Ca channels 3) Ca entry triggers exocytosis of synaptic vesicles 4) NE (neuroepinphrine) binds to adgrenergic receptor on target 5) receptor activation ceases when NE diffuses away from the synapse 6)NE is removed from the synapse 7) NE can be taken back into synaptic vesicles for re-release 8) NE is metabolized by monoamine oxidase (MAO) aCH synthesized from choline and acetly CoA 1) acetlycholine is made from choline and acetyl CoA 2) in the synaptic cleft, ACH is rapidly broken down by the enzyme acetylcholinesterase 3) choline is transported back into the axon terminal by cotransport with Na 4) recycled choline is used to make more ACH no transporter for ACH has to be broken down

Question 49

autonomic receptors have multiple subtypes (sympathetic adrenergic) (parasympathetic cholinergic)

Answer 49

sympathetic adrenergic (NE and E) receptors are all g-protein coupled receptors (metabotropic receptors) two main categories: alpha (most common) and beta with multiple subtypes parasympathetic cholinergic (ACH) receptors in target tissues are g-protein coupled receptors: muscarinic receptors M1, M2, M3

Question 50

g protein coupled receptors interaction with ion channels and interaction with membrane bound enzyme

Answer 50

interaction with ion channels: can lead to opening or closing of channel depending on g protein interaction with membrane bound enzymes: two main types: phospholipase C signal transduction pathway -inc in intracellular Ca mediates cellular response adenylyl cyclase signal transduction pathway -PKA phosphorylates proteins to cause a cellular response

Question 51

summary of pre and post ganglionic and parasympathetic/sympathetic

Answer 51

autonomic pathwyas consist of pre and postganglioonic neurons in series, with adrenal medulla being the exception preganglionic acetylcholine and post ganglionic is nictinic receptors sympathetic: most active uring stressful times most postgagnlionic is nonpinephrine--> target tissue adrenergic receptors (beta/alpha) preganglionic neurons orginate in lumbar and thoracic ganglia is located just outside spinal cord (paraverterbral) parasympathetic: most active during rest- and digest most postganglionic neurons acetlycholine --target tissue muscarnic receptors peganglionic orginate in brainsttem and sacral region of spine ganglia located on or near target tissue