nervous system Flashcards
action potential phase (5)
1) stimulus (threshold)
2) depolarization
3) peak of depolarization
4) repolarization phase
5) hyperpolarization phase
what cells are part of the CNS
ependymal
astrocytes
microglia
oligodendrocytes
what cells are part of the PNS
schwann
satellite
what cells produce myeline sheath
oligodendrocytes (CNS)
Schwann cells (PNS)
properties of cardiac tissue
involuntary
striated
pumps heart
one nucleus
what is muscle contractility
ability to forcefully contract when stimulated by an action potential
what layer is the epimysium
outermost
what is and what does hemoglobin do
a protein found in RBC that carries oxygen from lungs to the rest of the body
what is and what does myoglobin do
red protein in the sarcoplasm, only in muscle tissue, binds oxygen molecules, releases O2 as muscle fibres need it
what does the Z band do in a sarcolemma
separates one sarcomere from the next
what does the sarcoplasmic reticulum do and what comes out of it
fluid filled sac that encircles myofibril, stores Ca2+ ions
steps of contraction cycle
ATP hydrolysis
attachment of myosin to actin
power stroke
detachment of myosin from actin
what a neuromuscular junction does
where a somatic motor nerve comes into contact with a muscle
whats in a neuromuscular junction
synaptic end bulbs
synaptic cleft
motor end plate
high precision = fewer muscle fibres per nerve (2-20) for intricate precise muscle activity - fine motor
low precision = many muscle fibres (2000-3000) for gross movements
where do muscles get oxygen from
bloodstream
myoglobin
what affects muscle tone
small involuntary contractions\
tear in muscle
slow oxidative fibres
dark red
lots of myoglobin
generate ATP by aerobic respiration
slow speed of contraction
resistant to fatigue
fast oxidative glycolytic
red-pink
myoglobin
fast speed of contraction
generate ATPby aeriobic respiration
fast glycolytic
white/pale
few myoglobin
few mitochondria
lots of glycogen
generate ATP by glycolysis
fast speed on contraction
fatigue quickly
weight lifting
what is a trigger zone
segment where the next action potential is triggered
what is a synapse
the site of communication between neuron and effector cell
define slow axonal transport
speed 1-5mm/day
moves materials in ONE DIRECTION ONLY
define fast axonal transport
speed 200-400mm/day
moves materials BOTH WAYS
what is a nissl body
the endoplasmic reticulum in a neuron
what is the most common neuron in the body
multipolar
what is the largest / most numerous neuroglia in the body
astrocytes
what produces cerebrospinal fluid
Ependymal cells (CNS)
ligand gated
channels open or close when a chemical stimulus comes into contact
volted gated
opens in response to a change in the membrane potential
graded action potential
short distance communication
dendrites and cell body
action potential
long distance communication
trigger zone
what ions are moving in depolarization
Na+, K+, more Na+
electrical synapse
use gap junctions
faster communication
chemical synapse
transferred through synaptic cleft
3 ways to remove neurotransmitters from synaptic cleft
diffusion
enzymatic degradation
reuptake by cells
diverging circuits
one presynaptic neuron stimulates several postsynaptic neurons
converging circuits
several presynaptic neurons stimulate ONE postsynaptic neuron
what nervous systems work together to balance homeostasis
endocrine and nervous
what is present for regeneration of a neuron
Schwann cells
what makes speed of conduction faster
amount of myelination - More
axon diameter - larger
temperature - higher
perimysium
encircles groups of fibres into bundles of fascicles
what is a synaptic cleft
the gap between a presynaptic neuron and a postsynaptic neuron or muscle cell
what is saltatory conduction
propagation along myelin nerves
what is an interneuron
mostly inside CNS
a connecting neuron between sensory motor neurons
integrates sensory information and response and activates the motor neurons
