A & P Unit 3 Lecture Exam

- requires oxygen
- in mitochondria

aerobic respiration

6 second contraction
- produce enough ATP to meet needs

stored ATP

15 seconds contraction
- used to convert ADP → ATP
- produce enough ATP to meet needs

creatine phosphate

- in cytoplasm
- without oxygen
- 2.5 X faster than aerobic respir.
- produce enough ATP to meed needs

anaerobic respiration

↑ aerobic respiration

- cell uses oxygen in myoglobin
- cardiovascular + respiratory systems have ↑ O2 delivery to tissues → ↑ ATP production aerobically

as long as cardiovascular + respiratory systems can deliver sufficient O2 to tissues to make all ATP needed for contraction aerobically →

activity continues

what happens when cardiovascular + respiratory can no longer deliver sufficient O2 to tissues to make all ATP needed for contraction aerobically →

aerobic respiration also kicks in → continues for just a few minutes

what produces enough ATP to meet needs

1. stored ATP
2. creatine phosphate
3. anaerobic respiration

- the amount of O2 needed after exercise to return body to pre-exercise condition
- need O2 to resupply myoglobin w O2
- need O2 to ↑ ATP production aerobically

excess post-exercise O2 consumption (EPOC)

what is required for:
1. sweat to cool the body
2. adjust pH
3. have ↑ metabolism
4. reapair tissues

ATP

muscle fiber:
- have lots myoglobin (store O2)
- more capillaries + mitochondria
- smaller diameter
- fewer myofibrils
- adapted for aerobic respiration
- fatigue slow
- postural muscles, leg muscles

type I fibers (slow twitch red)

muscle fiber:
- less myoglobin
- fewer mitochondria
- fewer capillaries
- larger diameters → take longer for O2 diffuse through cells
- more myofibrils
- stronger contraction
- adapted for anaerobic respiration
- fatigue quicker, short period of time
- more enzymes in cytoplasm for anaerobic resp.
- store more glycogen
- quick mvmt muscles: eyes, hands, arms

type II B (fast twitch white fibers)

intermediate between type I and type II B

type II A (fast twitch pink/intermediate)

type of exercise:
- making muscles more "red"
- ↑ myoglobin
- ↑ mitochondria
- ↑ capillaries

aerobic exercise

type of exercise:
- make muscles big + strong
- anaerobic activity
- make muscles more "white"
- ↑ glycogen storage
- ↑ enzymes in cytoplasm for anaerobic resp
- make muscles bigger
- ↑ myofibrils in each muscle cell
- ↑ CT around muscle cells

strength training exercise

what makes muscles "bigger"?

↑ myofibrils in each muscle cell

motor units differ in:

1. number of muscle cells in motor unit (10-sev 100s)
2. sensitivity to stimuli (some respond to weak/strong)

only part of neuron that initiates impulses, send info to other neurons, muscle/gland cells

axon

part of neuron that receive info from environment, sensory receptors, other neurons

dendrites

one neuron + all skeletal muscle cells it contacts

motor unit

usually closed, opens in response to stimuli → allow calcium to diffuse in because more calcium outside cell than in

calcium channel

filled with Ach
- type of neurotransmitter

synaptic vesicles

Na+ channels, usually closed, open when Ach binds to them
- allow Na+ to enter because more Na+ outside cell than in

Ach receptors

single cx in response to single stimulus

muscle twitch

impulse travels along nerve, crosses to muscle at neuromuscular junction
- calcium released, cross bridges form

lag period

power stroke alternating with recovery stroke

cx phase

pump calcium back into S.R
- 0 cross bridges form
- 0 cx

relaxation

red

stimulus / lag period

blue arrow

cx phase

orange

relaxation

stronger stimulus reaches threshold more motor units
- more muscle cells cx

multiple motor unit summation

lowest stimulus where observational cx occurs
- threshold is just strong enough to reach threshold of motor unit

threshold stimulus

no ↑ in cx strength after this event
- lowest stimulus strength where all motor units respond

maximal stimulus

dark blue circle

subthreshold stimuli

value circled in light blue

threshold stimulus

value circled in pink

maximal stimulus

values in green

multiple motor unit summation

values in peach

supermaximal stimuli

more calcium available if partial relaxation → not all calcium returned to SR → more calcium = more cross bridges = stronger cx

wave summation
- partial relaxation between cx

muscle stimulated to cx again before it begins to relax

tetany
- sustained cx

purple

wave summation
- partial relaxation b/t cx

blue

tetany

still some tension on tendon if muscle not completely relaxed → less slack to take up

↑ frequency of stimuli
- tetany

change amount of overlap b/t actin + myosin filaments →

changes cx strength
- change length of muscle

optimum length for sarcomeres →

provides optimal overlap b/t actin + myosin
- change length of muscle

can form cross bridges →

gets lots of sliding of actin over myosin
- change length of muscle

overlap just enough so all myosin heads can bind to actin

change length of muscle

muscle too stretched = little overlap b/t actin + myosin

→ few cross bridges can from
→weaker cx
- change length of muscle

muscle too short = so much overlap, sarcomere so short

→ little sliding of actin over myosin
→ weaker cx
- change length of muscle

type of muscle:
- striated: has actin + myosin arranged into sarcomeres → alternating arrangement
- involuntary: can initiate its own impulse to cause heartbeat
- intercalated discs b/t cells
- less SR than skeletal muscle

cardiac muscle

highly folded PM b/t cells
↑ surface area
lots of desmosomes (hold cells together)

intercalated discs

calcium entering cell from extracellular fluid → release more calcium from SR

calcium induced calcium release

type of muscle:
- involuntary
- walls hallow muscular organs
- smooth, no striations
- actin + myosin filaments present, but not arranged into sarcomeres
→ arranged diagonally
- myosin filaments have heads along entire length
- no Z discs, has dense bodies instead that actin filaments attach to

smooth muscle

- actin + myosin present, not arranged into sarcomeres
- myosin filaments have heads along entire length

allow cx of very stretched muscle

type of muscle:
- has intermediate filaments
- no troponin
- little SR
can cx from impulse, hormones, stretching, local tissue conditions

smooth muscle

each cell must get its own impulse from neuron to cx
- each cell acts individually
- bronchi, walls of larger arteries, arrector pili muscles

multi-unit smooth muscle

cells joined by gap junctions
impulse travels cell to cell thru gap junctions
wave-like pattern of cx
most viscera
move something thru particular organ

single unit (visceral) smooth muscle

decrease in size of muscle b/c disuse or denervation
- < 1 year: muscle cells lose myofibrils, REVERSIBLE
- > 1 year: muscle cells die, replaced by scar tissue

atrophy

followed prolonged atrophy
- scar tissue shrinks, cause permanent flexing at the joints

contractures

- genetic disease
- mother → son
- lack of dystrophin protein
- smooth muscle affected
- contractures
- no cure
- no dystrophin: muscle cells tear to point they can't be replaced/repaired
→ muscle cells start to die, replaced by scar tissue

duchenne muscular dystrophy

- autoimmune disease
- women>men
- antibodies produced, block some Ach receptors on sarcolemma
- fewer Ach receptors produced → ↓ Ach binding to receptors
↓ muscle cx
- facial muscles affected first
- problems speaking, swallowing, control eye mvmts

myesthenia gravis

TX duchenne muscular dystrophy

- PT
- bracing
- walking + breathing assistance
- steroids to slow the progression

TX myesthenia gravis

- immune suppressing drugs, steroids
Ach-E inhibitors → inhibit breakdown Ach →more Ach binding to receptors

tear/stretch of muscle tissue
TX = RICE

strain

- weakness in organ wall, organ can protrude

hernia

most common hernia, in inguinal canal
- men>women due to larger inguinal canal

inguinal hernia

hernia in umbilical region
- second most common

umbilical hernia

hernia where small intestine returned to abdomen cavity manually

reducible hernia

hernia that is not reducible
- may become strangulated
- vessels of small int compressed → no blood supply to tissue → tissue dies

irreducible hernia

multiple layers of PM wrapped around axon

myelin sheath

- surrounded by myelin sheath
- insulates + protects axon
- ↑ speed impulse conduction

myelination of axons

type of cell that forms myelin sheath in peripheral nervous system
- line up along axon → wrap around axon many times → multiple layers PM wrapped around axon

schwann cells

all cytoplasm + organelles get squeezed to outer margins of schwann cells

neurilemma

areas of axon with no myelin (b/t myelinated areas)

nodes of ranvier

provide white color (white matter)

myelin/myelinated fibers (axon)

form myelin sheath in central nervous system
- has multiple flat extensions
- each wrap around part of axon many times → form myelin sheath

oligodendrocytes

when does myelin sheath begin forming?

before birth, not complete until adulthood

- autoimmune disease
- women>men
- destruction of myelin sheath in CNS
- immune system cells damage myelin in CNS
- replaced scar tissue
- interfere with impulse conduction
- ↓ muscle activity
- cognitive/balance impaired
- ↓ sensation
- burn/tingle sensation
- facial muscles affected first (slurred speech, difficult swallowing)

multiple sclerosis

TX multiple sclerosis

immune suppressing drugs
plasma phoresis

classification of neurons

1. structure
2. function

type of neuron classified by structure:
- 99% neurons
- many dendrites, one axon
- all motor neurons
- all association neurons (interneurons)

multipolar neurons

type of neuron classified by structure:
- 2 cytoplasmic extensions with cell body b/t
- 1 axon, 1 serves as dendrite
- some sensory neurons (eyes, nose)

bipolar neurons

type of neuron classified by structure:
- one long cytoplasmic extension, neuron cell body to side
- distal, unmyelinate = dendrites
- myelinated = axon

unipolar neurons

type of neuron:
- most unipolar, some bipolar
- body → CNS

sensory neuron

type of neuron:
- CNS → body
- muscles/glands
- all multipolar

motor neurons

type of neuron:
- interconnecting neurons/association
- carry info neuron to neuron in CNS
- all multipolar

interneurons

- gray matter
- info integrated, processed, decisions made
- most in CNS

clusters neurons cell bodies

where is gray matter located in CNS

- outer surface brain "cortex"
- inner regions spinal cord
- nuclei : other clusters neuron cell bodies

where is gray matter in peripheral NS

ganglion

clusters neuron cell bodies (gray matter) in peripheral NS

ganglion

white matter

myelinated axons

- carry info place to place

white matter - myelinated disc

bundles of white matter in CNS

tracts

carry info place to place in brain or b/t brain + spinal cord

tracts

bundles of white fibers in peripheral NS

nerves

carry info back and forth from body to CNS

nerves

make up the control system

nervous + endocrine

nerve impulses + neurotransmitters

nervous system

communicate with hormones

endocrine system

part of NS that includes brain + spinal cord only

CNS