BIOL 118 UNIT 2 PT 2

nervous system transport channels

astrocytes

star shaped supporting nervous system cell that cling to neurons and connect them to blood capillaries which act as nutrient supply line

brain capillaries

have tight junction and an additional layer of cells to prevent extracellular substances from getting to the brain/CNS

sensory receptor, sensory input, integration, motor output, effector

order of signaling from seeing someone to waving your hand (include 5)

autonomic

characterizes motor responses from glands and cardiac/smooth muscles

somatic

characterizes motor responses from skeletal muscles

efferent neurons

carry motor information away from the central nervous system to the muscles and glands of the body in order to initiate an action

afferent neurons

carry information from sensory organs/receptors carried towards the CNS

peripheral nervous system

consists of all nerves connecting the body and CNS, responsible for sensory signaling and sending out motor responses

central nervous system

consists of brain and spinal chord, does decision making

sensory input

gathered information from stimuli

integration

processes and interprets sensory input and decides what should be done at each moment

motor output

causes a response/effect that activates muscles/gland effectors

glial cell

group of different cell types whose function is to support the nervous system

schwan cells

glial cells that form a myelin sheath around axons to create fatty acid insulating layers

myelination

the act of a lipid bilayer wrapping around axon multiple times to create insulating layers

axons

long threadlike part of nerve cell that connects cell body and carries signals/impulses away from it

hillock transition

cone like region connecting cell body and axon

neurons/nerve cells

highly specialized cells who transmit messages from one part of the body to another, all have a cell body and one or more thin protrusions

cell body

metabolic center of a nerve cell that contains all the expected cell organelles except centrioles

axon terminal

ends of an axon that contain vesicles with neurotransmitter chemicals which are sent to the next neuron

fascicles

connective tissue columns that make up neuron structure

node of ranvier

regions in the axonal membrane that are not insulated by myelin

dendrite

neuron processes that convey information towards the cell body

chemical synapse

connections between two neurons, one axon sends chemical signaling that will effect the next

microtubule highway

runs the length of axon and helps move things such as nutrients and proteins from the cell body to other parts of the cell, moves molecules both ways

alzheimers disease

disease in which misfolded proteins in microtubule highway structure make it unable to properly function

integration in CNS

control center in reflex signaling

irritability

ability to respond to stimulus and convert it into nerve impulse

conductivity

ability to transmit impulses to other neurons, muscles, or glands

K+

major positive ions in the intercellular space

Na+

major positive ion in the extracellular space

graded potential

a local change in the electrical potential on a membrane that varies directly with the strength of the stimulus

depolarization

intracellular space in made more positive

hyperpolarization

intracellular space is made more negative

action potential

an electrical event occurring when a stimulus of sufficient intensity is applied to a neuron or muscle cell, allowing sodium ions to move into the cell and reverse the polarity

nerve impulse

all or nothing signal sent over the entire axon also called action potential

ligand gated ion channel

membrane protein channels which allows the regulated flow of selected ions across the plasma membrane when opened by another protein

threshold

point in which the membrane completely depolarizes and an action potential is produced

Na/K voltage gated channel

mediate the generation of action potentials, which allow signals to be propagated from one end of a neuron to the other 

voltage sensing alpha helix

part of na/k ion gated channel that at rest is attracted to the negative side of the cell membrane, and its movement due to depolarization opens the channel

channel inactivation segment

leaves the Na/K channel refractory/unable to open again for a period of time, occurs due to random motion

K voltage gated channels

weird shape makes it slower to open and close opposed to Na+ channel, closed at resting potential, responsible for returning cell to polarized resting potential

sub threshold accumulation

stimulus from neuron causes depolarization, but not enough to reach threshold to cause action potential

temporal summation

neuron fires twice opening some channels, then immediately opening more a second time and reaches threshold

spatial summation

two neurons both depolarize and reach threshold

spatial summation of EPSP/IPSP

signaling stimuli applied at the same time with a cumulative effect on action potential

excitatory post synaptic potential

a temporary depolarization of postsynaptic membrane caused by the flow of positively charged ions into the postsynaptic cell as a result of opening of ligand-sensitive channels

inhibitory post synaptic potential

a signal that causes a Temporary hyper polarization and prevents an action potential from being fired

1. depolarization phase, 2. re polarization phase, 3. undershoot

steps of action potential

undershoot

due to slow closing of K+ channel more K+ ions exit and creates a brief period of hyper polarization

non decremental

describes action potentials on/off characteristic, the voltage is the same across the axon and travels in one direction

myelin sheath

ensures extracellular charges don’t interact/effect intracellular ions

sarcomere, myofibril, myocyte, fascicle, organ

order parts of muscle from smallest to largest

fascicle

bundle of myocytes

myocyte

muscle cell, we have all we will ever have post birth

myoblast

type of stem cell during embryonic development that fuse to form one long myocyte

satellite cells

multipotent myoblasts that cannot form new muscle cells but are used for muscle repair

myofibril

many rod like organelles that make up muscle cells that can be added to and build muscle mass

sarcomeres

smallest functional unit of muscle contraction that make up myofibrils

thick filament

composed of myosin proteins whose heads attach to oppositely oriented thin filaments, actin, and pull them past one another

myosin

fibrous protein that makes up thick filament, has a clear head and tail shape

thin filament

composed of actin proteins and regulatory proteins for the binding of the myosin head, anchored to the z-disk

sarcoplasmic reticulum

specialized organelle whose main function is to store and release calcium ions

active transport

mechanism that returns calcium to the SR

T tubule voltage sensor

voltage sensitive membrane protein that when depolarized in the t tubule changed the conformation of the Ca channel in the SR

acetylcholine

neurotransmitter that binds to ligand gated channel of the synaptic cleft and allows Na and K into muscle cell

acetylcholinesterase

enzyme that breaks down/removes ACH from ligand gated channel to terminate signal

tropomyosin

blocks myosin binding site on the thin filament

troponin Ca 2+ complex

when activated removes tropomyosin from myosin binding site

sarcolemma

tubular sheath that envelopes muscle fibers

blood, bones

origin of extracellular Ca2+

calcium channels

when action potential reaches axon terminal it opens these which signal vesicles to cary neurotransmitters to axon membrane

Na/K pump

bring membrane back to resting potential when a brief period of hyper polarization is created during the “undershoot” phase

synaptic cleft

the space after the axon terminal of a neuron between the next target cell

cross bridge

the link formed when a myosin head binds to the corresponding myosin binding site during contraction

myosin heads detach from actin

step of cross bridge cycling that requires ATP

hypertrophy

increase and growth of myofibrils

atrophy

shrink/degeneration of myofibrils

quiescent

resting state most satellite cells are in

multipotent

satellite stem cells differentiation state

parasympathetic

rest and digest

sympathetic

fight or flight

skeletal

somatic muscle

cardiac, smooth

autonomic muscles

sensory neuron

“input” neuron, responds to stimuli receptor

motor neuron

“output” neuron, goes to effector

“stored” ATP

first energy source for active skeletal muscle

creatine phosphate

second energy source for active skeletal muscle after stored ATP runs out

aerobic glycolysis and lipolysis

2 processes use oxygen to create ATP in mitochondria

oxygen debt

occurs after performing strenuous exercise, body can no longer distribute oxygen to muscle cells to aid the processes that make them function and more is needed to restore energy

lactate

waste product of anaerobic glycolysis

liver, blood, mitochondria in resting muscle cell

path fatty acids take from storage to being converted to ATP via anabolism during rest

liver

where oxygen debt is paid through glucogenesis

GLUT4, CP, mitochondria, myoglobin

organelles/proteins red type I muscle cells have more of

SR, Glycogen

organelles/proteins white type II muscle cells have more of

myoglobin

protein whose main function is to supply oxygen to the cells in your muscles 

red muscle cells

type of muscle cell: small, many capillaries, use lipids for energy

white muscle cells

type of muscle cell: large, few capillaries, use glycogen for energy

white muscle cells

muscle type better for sprinting, weight lifting

red muscle cells

muscle type better for endurance running