AP exam 3

two methods of long istance signaling

Hormonal signaling

neuronal signaling 

CNS

Comprises the brain and spinal cord

PNS

extends from the spina cord to the rest of the body

Somatic nervous system

Controls voluntary movements

e.g. wlking and talking 

Autonomic nervous system 

Regulates involuntary movements; innervatees visceral organs and glands

e.g. breathing, digestion, heart rate 

Afferent nerves

Sensory information Into the CNS

Efferent nerves

information away from the CNS

enteric Nervous system

controls motility/ activity in the digestive tract

Neuroglial cells

support the neurons ( non-transmitting cells)

Schwann cells, oligodendrocytes, migroglia etc. 

neurondss become activated when graded potentil raises to the ?

threshold potential

which division of the PNS is responsible for the fight or flight response

sympathetic

excitable cells

cells that use movement of electrolytes in/ out of the cell to generate an electrical current

initial part of the axon that transforms the grade potential into action potential

Axon hillock 

terminal buttons

store/ relesse vessicles containing neurotransmitters 

neurotransmitter

chemical messenger molecules that act on target cells

types of synapse junctions

• neuron to neuron 

• neuro-muscular

• neuro-glandular 

Main inhibitory neurotransmitter of the CNS 

GABA

Main excitatory NT in the CNS

Glutamate

Major NTs

Catecholamines 

• Norepinephirine

• epinephiring

• DA ( dopamine)

• Serotonin

• Acetylchoine 

• endorphins

Norepinephrine function

NT for fight or flight

epinephrine function

circulating hormone for fight or flight

dopamine main function

award/ pleasure 

muscle control parkinsons

serotonin function

• mood hormone

  • muscle control, digestive tract control

Acetylcholine function

PNS: control of afferent and efferent nerves

CNS: involved in memory and thinking pathways

Endorphins

Natural agonists of opiod receptors

inhibits pain signaling, can also cause euphoria

three classes of neurons

• afferent neurons

• efferent neurons 

• interneurons 

interneurons

connect one neuron to another

all wihin the CNS

99% of neurons in humans

membrane potential (mV)

sepertion og electrical charges across a cell membrane

resting membrane potential

the membane potential when the cell is at est

• no ions flow in/ out of cell

T or F: Action potentials must be started by a graded potentia in the neuronal cell body

True

Axtion potentials begin at

the axon hillock

T or F: Action potentials are conducted segment by segment along the axon 

true 

two types of axon conduction

• contigous conduction ( unmyelinated)

• Saltatory conduction ( myelinated)

why do signals move in only one ditection

the ions only open the front door of each voltage channel allowing it to only move forward

how do local anesthetics work 

by bonding and inhibiting  voltage gated Na+ channels

no Na+ → no AP → no spreding depolarization

myelin

lipid rich insulator of conduction

nodes of Ranvier

unmyelinated gaps

unmyelinated conduction ( contigous) 

• afferent c-type neurons 

• nociception, temp., itch, gentle touch 

• move much slower 

Type A neurons

Largest,fastest most myelinated

efferent: motor neurons 

afferent: proprioception ( muscles), fast pain reveptors, sensitive touch receptors 

Type B neurons

medium speed

Afferent: visceral senses 

efferent: autonomic within the spina cord 

NT function ends when

they are removed from the synaptic clet

three mechanisms NT use to terminate signas

1. transported back into the axon terminal by reuptake carriers 

2. inactivation/ destruction by an enzyme 

3. diffusion away from the synaptic cleft 

two classes of cells in the CNS 

• neurons: transmitting cells

• Neuroglial cells: non-transmitting/ supporting cells

Astrocytes

• support neuron structure and alignment

• support blood brain barrier

• most abundant neuroglial

• facilitates glucose absorption

Oligodendrocytes 

• creates myelin sheaths in CNS

• one olig. myelinates multiople axons

• increases speed of action potential; reduces ATP usage

Ependymal cells

• line spces sin the brain and spina cord 

• forms cerebrospinal fluid

Microglia

• immune defense cells in CNS 

• phagocytic cells 

what is grey matter comprised of 

cell bodies and glial cells 

what is white matter comprised of

myelinated axons

where do efferent spinal neurons begin?

in the ventral horn of the spinal cord

where do sensory affernt neurons end

the dorsal horns of the spinal cord

Brainstem 

• connects brain to spinal cord

• controls breathing, heart rate swallowing

•  medulla oblongota, pons, midbrain

MAOI drugs increase__?

the amount of DA, serotonin and norepinephrine stores in the neurons

DA, serotonin and norepinephrinf are metabolized by__?

monoamine oxidase 

(MAO-A and MAO-B) 

Diencephalon

thalamus- inputs/outputs

hypothalmus- integrates CNS woth endocrine system 

cerebellum function

• conrols balance and coordination of movements

• involved oin motor learning 

• receives info from visua land auditory senses 

Medulla oblongota

• contains cardiac, respiratory, vomiting and vasomotor centers

• swallowing, coughing, sneezing

• autonomic nervous system control

Pons- middle part

• cranial nerves connect here for respiration, eye movement, facial sensations, and facial movements 

• urination control, breathing aids 

• pain receptor processing from the neck down 

Midbrain

• coordinates reflex responses to sight and sound

• sleep/ wakefulness paterns 

• thermoregulation 

damage to cerebellum

• abstract reasining/ planning difficulties

• speech issues

• changes in personality

the hypothalamus is responsible for what four F’s?

• feeding

• fighting

• fleeing

• fornicating

hypothalamus

contol center for homeostasis in the body

• sends hormones to APG and PPG

hormones sent to anteriior pituitary gland (APG)

• sex hormones 

• thyroid hormones 

• stress hormones

• growth hormones

hormones sent to the posterior ptuitary gland (PPG)

• vasopressin 

• oxytocin 

Thalamus

• relay all sensory inputs ( except smell) 

• contra-lateral pathways ( dessucation in brain) 

• memory recall

• relays outgoing motor instructions 

functional area of cerebral cortex

Primary cortices- direct input/ control

Association cortices- complex planning, self-awarness, language, personality 

Fiber tracs(White matter)- transmmit signals from one area to another 

__ connects the two cerebral hemispheres

corpus callosum