Anatomy Exam 3

Everything

Describe how connective tissue is part of a skeletal muscle

Connective tissue forms sheaths around the entire muscle, bundles of muscle fiber, and individual muscle fiber.

Explain why a skeletal muscle is properly classified as an organ.

Because muscle is formed of specialized cells that are working together to generate forces.

Name the major parts of a skeletal muscle fiber and describe the function of each.

• Sarcolemma: regulate movement ions for contractions

• sarcoplasm: facilitate muscle contraction

• myofibrils: acts as contractile units

• sarcomeres: shorten and cause contraction

• sarcoplasmic reticulum: calcium storage and release system

Name the parts of a skeletal muscle

1. Filaments

2. Myofibril

3. Sarcoplasmic reticulum

4. Nuclei

5. Sarcolemma

6. Endomysium

7. Perimysium

8. Epimysium

9. Fascile

10. Fiber

What does a neuron release to stimulate a contraction in the muscle?

Neurotransmitter acetylcholine

What causes the sarcoplasmic reticulum to release calcium?

Action Potential

What does calcium do?

gets released from sarcoplasmic reticulum and binds to troponin which causes tropomyosin to move

How does ATP influence the interaction between actin and myosin?

ATP binding causes myosin to detach from actin

When the neuron stops signaling, what promotes relaxation?

The neuron stops releasing acetylcholine

What is rigor mortis?  When does it happen?  Why does it happen?  Explain how this stiffening occurs with respect to aspects of the contraction cycle.

the temporary stiffening of muscles after death, typically beginning 3-12 hours postmortem, and is caused by a lack of adenosine triphosphate (ATP) which prevents muscle relaxation

Explain how the muscle fiber contraction mechanism obtains energy.

From ATP, which is used to power the sliding filaments (actin and myosin)

The night before racing, most marathon runners eat meals that are high in carbohydrates, like pasta.  Explain how this carbo-loading helps their muscles during the race.

increasing the body's stores of glycogen, the form in which muscles store glucose for energy

Explain the logic of taking a creatine supplement.  Also describe why creatine is not as good as some people make it out to be.

1. to increase its stores in the muscles, which provides more fuel for high-intensity exercise by helping to regenerate adenosine triphosphate (ATP), leading to improved strength and power

2. it does not work for everyone, it does not improve endurance in the same way it does high-intensity performance

Describe why/how a muscle may become fatigued/cramped.

depletion of energy sources like ATP and glycogen, the buildup of metabolic byproducts like hydrogen ions, and imbalances in electrolytes such as potassium and calcium

Explain how muscles move bones

contracting and pulling on bones through tendons

Explain how muscles work together to coordinate movement

where one muscle contracts to produce a movement (the agonist) while the opposing muscle relaxes to allow that movement (the antagonist)

muscle fiber

single muscle cells

myosin

protein that interacts with actin to form filaments for muscle fiber contraction

actin

protein in a muscle fiber that forms the thin filaments that slide between filaments of the protein myosin, shortening the muscle fibers

sarcoplasmic reticulum

specialized network of membranes in muscle cells that regulates muscle contraction and relaxation by storing, releasing, and reabsorbing calcium ions

transverse tubules (T tubules)

membrane tube of interior of cell

epimysium

connective tissue surrounding fascicles and perimysium

perimysium

connective tissue around fascicles

endomysium

connective tissue around muscle cell/fiber

fascicles

bundles of fibers surrounded by perimysium

myofibrils

bundles of filament

agonist

does the movement

synergist

multiple muscles working towards a goal/movement

antagonist

undoes the movement

origin

non moveable attachment

insertion

moveable attachment

motor neuron

 neuron that conduits impulses from the central nervous system to an effector

neuromuscular junction

location where a neuron axon and skeletal muscle fiber meet

motor end plate

region of a skeletal muscle fiber's membrane where it connects with a motor neuron's axon terminal, forming neuromuscular junction

neurotransmitter

signaling molecule 

acetylcholine

binds to receptor on muscle fiber

creatine phosphate

a high-energy phosphate compound found primarily in muscle cells

rigor mortis

muscles are retracted and stiff because ATP isn’t being preplenished (happens in death)

ATP

energy of a cell

glycogen

polysaccharide that stores glucose in the liver and muscles

muscle cramp

a sudden, involuntary contraction of a muscle that causes pain and stiffness

central nervous system

brain and spinal cord

peripheral nervous system

cranial and spinal nerves

sensory division

the part of the nervous system that detects and transmits sensory information from the body to the central nervous system (CNS)

motor division

a part of the peripheral nervous system that transmits impulses from the CNS to the body's organs and muscles

somatic nervous system

controls voluntary movements

autonomic nervous system

controls involuntary bodily functions 

effectors

a muscle or gland that effects change in the body

neuroglia cells

nourish and maintain neurons (nerve glue)

gliomas

a group of brain tumors that originate from glial cells

microglia

small, spiderlike cells scattered through the CNS, proliferate during inflammation

oligodendrocytes

produce myelin sheath around nerve fibers of the CNS

myelin sheath

lipid material that forms a sheathlike covering around some axons

white matter

a type of tissue found in the brain and spinal cord

gray matter

grayish nerve tissue of the central nervous system

Schwann cells

encase axon of PNS in myelin sheaths, protect and help action potential

astrocytes

support and structure, between blood vessels and neurons

ependymal cells 

line the cavities of the brain and spinal cord

cilia

moves things in the cell

neurons

relay messages from body to brain

dendrites

process of a neuron that receives input from other neurons

axons

nerve fiber, conducts an impulse away from a neuron cell body

nodes of ranvier

any of the many gaps in the myelin sheath along axons of neurons of the PNS

sensory/afferent neurons

transmit sensory information from receptors to CNS

interneurons

neuron within the CNS between a sensory neuron and a motor neuron

motor/efferent neurons

nerve cell that carries signals from CNS to muscles, glands, and other effector organs

synapse

functional connection between neurons

synaptic cleft

a narrow extracellular space between the cells at a synapse

neurotransmitter

signaling molecule

membrane potential

difference in electrical charge between inside and outside of cell

resting potential

electrical charge difference across a cells membrane when it is not transmitting a signal

equilibrium

state of balance

active transport

process that requires energy and a carrier molecule to move a substance across a cell membrane

anions

negatively charged ions

polarized

the electrical charge difference across a cell membrane. where one side is more positive and the other is more negative

depolarized

the membrane of a neuron becomes less negative than the resting potential

hyperpolarized

increase in the negativity of the resting potential of a cell membrane, threshold is farther away

repolarize

the membrane potential of a neuron returning to its negative state

threshold

the minimum electrical charge required to trigger a neural impulse, or action potential

action potential

all-or-nothing electrical impulse that allows neurons to communicate by sending a signal down the axon

chemoreceptors

receptor stimulated by the binding of certain chemicals

pain receptors

sensory nerve ending that triggers impulses interpreted as pain

thermoreceptors

sensory receptors sensitive to temperature

mechanoreceptors

sensory receptor sensitive to mechanical stimulation (pressure or tension)

photoreceptors

 sensory receptor sensitive to light 

chemically gated sodium channel

 type of ligand-gated ion channel that opens in response to a chemical messenger, such as a neurotransmitter, allowing sodium ions to flow across the cell membrane.

Voltage gated sodium channel

transmembrane proteins that create a rapid influx of sodium ions into a cell in response to a voltage change

Voltage gated potassium channel

membrane proteins that open and close in response to changes in electrical voltage, allowing potassium ions to pass through the cell membrane

nervve impulse

signal a nerve sends to the brain

synaptic knob

tiny enlargement at the end of an axon that secretes a neurotransmitter

synaptic vesicles

small, membrane-bound sacs inside the presynaptic terminal of a neuron that store neurotransmitters and release them into the synaptic cleft to communicate with another neuron

saltatory conduction

an electrical signal jumps from one gap in a nerves myelin sheath to the next, this allows for faster and efficient nerve impulse transmission

alzheimers disease

a progressive brain disorder that causes memory loss, confusion, and other cognitive decline

parkinsons disease

a progressive neurological disorder that affects movement

huntingtons disease

 a rare, inherited neurodegenerative disorder that progressively affects a person's movements, cognitive abilities, and mental health

atrophy

shrinking of an organ or tissue

reflex

automatic response to stimulus

perceiving

mental interpretation of sensory stimulatioin

general senses

touch, pressure, pain, temperature, length and tension of muscles, visceral senses

special senses

vision, hearing, taste, smell, equilibrium