ANS 2140 Nervous System

Central nervous system

brain/spinal cord, control center, sends/receives signals

Peripheral nervous system

communicates CNS to rest of the body, 2 parts- sensory + motor

sensory system

senses change, somatic + visceral nerve fibers, impuse from receptor to CNS

Motor system

motor nerve fibers, impulse from CNS to effectors, 2 parts- somatic and autonomic

somatic nervous system

voluntary, impulse from CNS to skeletal muscles

Autonomic nervous system

involuntary, impulse from CNS to cardiac/smooth muscle, 2 parts- sympathetic and parasympathetic

sympathetic nervous system

fight or flight

parasympathetic nervous system

rest and digest

nerve cell types

neurons and glial cells

neurons

carry electrochemical gradient

glial cells

supportive cells

neuroglial cell types

astrocytes, microglial, ependymal, oligodendrocytes, schwann cells, satellite cells

astrocytes

CNS, highest component, housekeeping

Microglia

CNS, immune fraction

Ependymal

CNS, line spinal column, produce spinal fluid

oligodendrocytes

CNS, keep signal, myelination 1: many neurons

Schwann cells

PNS, keep signal going, myelination 1:1

Satellite cells

PNS, neuroregenerative

dendrites

receive signal

cell body/soma

single nuclei, acts like normal cell

axon

carries signal in one direction away from soma

axon hillock

where cell body and axon meet, threshold must be met for signal to pass

Myelin sheath gap

between schwann cells

axon terminals

secrete neurotransmitters to other cells

properties of neurons

excitability, conductivity, secretion

ligand-gated channel

chemical binds to channel to open for molecule to enter cell

mechanically-gated channel

physical change causes channel to open, pressure/temp change

voltage-gated channel

opens in response to change in response in membrane potential

Resting membrane potential

-70mV, inside memb=negative, outside memb= positive

depolarization

reduce memb potential toward 0, fast voltage gated Na channels open, Na enters

repolarization

memb potential moves toward baseline, Na channels plug with ball and chain

hyperpolarization

memb potential goes below baseline, slow voltage gated K channels allow more K out than Na was let in

Na/K ATPase

pumps Na/K across membrane to get back to resting membrane potential

absolute refractory period

time where second action potential cannot happen

relative refractory period

need greater stimulation for second action potential

mylenation

insulation, 20% protein 80% fat

nodes of ranvier/myelin sheath gap

where action potential/stimulation occurs

chemical synapse

neurotransmitter sent from a neuron to another

electrical synapse

uses electrical signals to communicate between 2 cells

receives exciteable signals

axodendritic and axosomatic synapse

receives irritable signals

axoaxonic synapse

ways a neurotransmitter is terminated

reuptake, enzymatic degradation, and diffusion away from synapse

skeletal muscle

multinucleated, bone, striated, voluntary

cardiac muscle

1-3 nucei, involuntary, striated, heart

smooth muscle

1 nucleus, hallow organs, not striated, involuntary

muscle functions

produce movement, maintain posture/body position, stabilize joints, generate heat

characteristics of muscle

responsiveness, conductivity, contractility, extensibility, elasticity

hyperplasia

increase in cell number, before birth

hypertrophy

increase in cell size, after birth

muscle twitch

response of a muscle to a single brief threshold stimulus, graded response

multiple motor units

fine motor skills and posture

muscle absolute refractory period

NONE

tropamyosin

long thin regulatory protein that covers binding sites

troponin

regulates tropamyosin and is regulated by calcium

rigor mortis

deterioration of sarcoplasmic reticulum

ATP used in…

detachment of the cross bridge, pumping calcium into the sarcoplasmic reticulum, and pumping Na out and K in after E-C coupling

ways to make ATP

direct phosphorylation, glycolysis, oxidative phosphorylation

direct phosphorylation

phosphocreatine + ADP → ATP, 1:1 ratio, lasts 15 seconds

glycolysis

Glucose→ATP, anaerobic, 1:2 ratio, lasts 30-40 seconds

oxidative phosphorylation

aerobic, 1:32-36 ratio, lasts hours, uses amino acids and fatty acids

Red muscle

slow oxidative, many capillaries + myoglobin + mitochondria

white muscle

fast glycolytic, few capillaries + myoglobin + mitochondria

fast oxidative

middle fiber type

skeletal system functions

support, protection, anchorage, mineral/growth factor storage, blood cell formation, fat storage, hormone production

axial skeleton

protection, support, carry all other body parts

appendicular skeleton

movement and manipulating the environment

hyaline cartilage

most abundant, most joints, sternum, larynx, nose

elastic cartilage

repeated bending/movement, epiglottis and ear

fibrous cartilage

row of chondrocytes and thick collagen fibers, knee, discs of vertebrae

bone composition

inorganic (calcium phosphate, hardness) and organic (carbon, tensile strength)

tensile strength

allows for flexibility before breaking

epiphysis

ends of bone

diaphysis

middle shaft of bone

osteon

funtional unit

lacuna

contains cells that sense environment, part of osteon

osteogenic cell

mitotically active, make osteoblast + osteocytes + bone lining cells, found on inside and outside of bone

osteoblast

bone building, secrete osteoid for tensile strength

osteocyte

monitor and maintain bone inside

bone lining cells

monitor and maintain bone on the outside

osteoclasts

bone cutting cells at resorption site

types of bone growth

bone formation, direction, bone remodeling

bone formation

endochondral ossification- embryonic bone growth, uses hyaline cartilage + intramembranous ossification- uses fibrous cartilage

direction

lengthening- at epiphyseal plates, and appositional- increase in bone width

bone remodeling

bone resorption- osteoclasts come in and cut away bone and bone deposition- osteoblasts secrete osteoid, mineralization follows

resting zone

not doing anything, closest to epiphysis

proliferation zone

cartilage cells undergo mitosis

hypertrophic zone

chondrocytes undergo hypertrophy and push up to lengthen epiphysis

calcification zone

cells die and matrix comes in, calcifies/hardens

ossification zone

osteoclasts first cut away calcified matrix + osteoblasts lay down osteoid, mineralization occurs