Anatomy 1. Unit 3 Review

What are the 3 muscle tissues?

Skeletal muscle, cardiac muscle, smooth muscle.

Define skeletal muscle?

Voluntary, striated, multiple nuclei, parallel.

Define cardiac Muscle?

Involuntary, striated, intercalated disc, and branched

Define smooth muscle

Involuntary, NO STRIATIONS, spindle shaped, found in hollow organs

What are the characteristics of muscle?

Excitability, Extensibility, Contractility, Elasticity

What is the function of muscle?

movement, posture maintenance, heat production, and joint stabilization

What is the order of organization of SKELETAL muscles?

Sarcomeres, myofibrils, muscle fiber/cell, fascicles, connective tissue layers(endomysium, perimysium, epimysium)

What are the 4 special parts of a muscle cell?

Sarcoplasmic reticulum, sarcolemma, sarcoplasm , myofibrils

Define sarcoplasmic reticulum?

Calcium storage and release

Define Sarcolemma?

Muscle cell plasma membrane

Define Sarcoplasm?

Cytoplasm containing glycogen and mitochondria.

Define myofibrils?

Bundles of sarcomeres

Understand all of the parts of a sarcomere?

Smallest contractile unit containing actin and myosin filaments.

Sarcomeres: H ZONE

contains only myosin, myosin in anchored to the M-line in this zone

Sarcomeres: I BAND

Contains only actin

Sarcomeres: A BAND

Contains actin and myosin

Sarcomeres: M- LINE

Anchors myosin

Sarcomeres: Z DISC

Anchors thin filaments

What does actin do?

thin filaments. Slides over myosin during contractions. Has Myosin Binding Site for Myosin head attachment

What does myosin do?

Forms thick filaments

How does actin and myosin work with each other?

Muscle contraction occurs by sliding filament mechanism where myosin heads pull actin filaments toward the M line, shortening the sarcomere.

What are the events of a muscle contraction?

Muscle contraction occurs by sliding filament mechanism where myosin heads pull actin filaments toward the M line, shortening the sarcomere

What is the role of tropomyosin?

Blocks myosin binding sites on actin

When a muscle goes through contraction the ____ zone and the ____ band become ___

H zone, I zone, smaller

When a muscle goes through contraction the H zone and I band start disappearing because

The actin is moving towards the myosin creating more and more overlap

What is the role of Troponin?

Binds calcium, causing tropomyosin to move and expose binding sites.

What is the role of calcium in muscle contractions?

Triggers contractions by binding to troponin. When ___ is released it binds to troponin and this causes troponin to change its shape.

What is acetylcholine?

A Neurotransmitter released at the neuromuscular junction to initiate muscle contraction.

What is the role of ATP(energy) in a muscle contraction?

It removes calcium from troponin and to reverse the reaction so the contraction stops

What is the neuromuscular junction NMJ?

The synapse point between a muscle cell and axon terminals

What events happen in the neuromuscular junction NMJ?

depolarization and contraction events. where a neurotransmitter is released Acetylcholine =Ach from the axon terminals and goes across the synaptic cleft to the muscle cell to eventually bind and excite the muscle cell

Define muscle tone?

All of your muscles remain in slight, partial contraction, This keeps them from being flaccid

Define and understand motor nerves=neurons?

Nerve cell controlling muscle fibers

Motor nerve contains axons of up to hundreds of___

motor neurons

Each muscle is served by at least one ____

motor nerve

Define motor unit?

the nerve muscle functional unit

Define isotonic contraction?

contraction of muscle in which effort overcomes the load and movement occurs

What are the 2 subtypes of isotonic?

Concentric: muscle shortens as it contracts *think of doing a bicep curl, eccentric: muscle lengthens as it contracts *think of you curling your bicep and then putting the weight back down, the bicep must still be contracting as you stretch it or otherwise the weight you are holding would just be thrown/dropped to the ground

Define isometric contractions?

Muscle strength stays the same, force generated but no movement *think about pushing against a wall, muscles are contracting but the wall isn’t moving

What is the function of the nervous system?

Controls and coordinates body activities

Define the central nervous system?

consists of the brain, brain stem, and spinal cord

Define the peripheral nervous system?

Outside of the brain: Consists of the brain stem, spinal cord

define the sensory nervous system?

Afferent! Carries signals to the central nervous system.

Define the motor nervous system?

Efferent! Carries signals from the central nervous system to muscles/glands.

describe the function of the axon?

Transmits impulses away from the cell body

describe the function of the Cell body?

Contains nucleus and organelles

describe the function of the Dendrite?

Receives incoming signals

describe the function of the Myelin?

Insulates axon, speeds impulses

describe the function of the Nodes of Ranvier?

Gaps in myelin enhancing impulse speed

describe the function of the Schwann cells

Forms myelin sheath in peripheral nervous system. ”myelinate axons in PNS”

describe the function of the Terminal bulb?

Synaptic end releasing neurotransmitters

describe the function of the Axon hillock?

Initiates nerve impulses

Neuron classification: structural (list them)

multipolar, bipolar, unipolar

Neuron classification: functional (list them)

sensory (afferent), motor (efferent), interneurons

What is the function of Oligodendrocytes?

“Myelinate axons in the CNS” central nervous system

What is the function of Microglia?

Immune defense in the central nervous system

What is the function of Astrocytes?

Supports, blood brain barrier

What is the function of Ependymal cells?

Line CNS cavities, involved in CSF production

What is the function of Satellite cells?

Supports PNS neuron cell bodies

What is the process of myelination?

Process of wrapping axons with myelin

What is the purpose of myelination?

to increase conduction velocity of nerve impulses

Outline the events which occur during the transmission of a nerve impulse. Include resting membrane potential, depolarization, repolarization, hyperpolarization, refractory period, Na+/K+ pump, Na+ and K+ gates (channels), and gates.

• Resting membrane potential maintained by Na+/K+ pump.

• Depolarization: Na+ channels open, Na+ enters cell.

• Repolarization: K+ channels open, K+ exits cell.

• Hyperpolarization: Membrane potential becomes more negative than resting.

• Refractory period: Time when neuron is insensitive to stimulus.

Define saltatory conduction

Impulse jumps between nodes of Ranvier, faster transmission.

Define continuous conduction?

Impulse travels along entire axon unmyelinated

What is the all or none law as it applies to the nerve impulses?

Neuron fires fully or not at all

Outline the events which occur as a nerve impulse is relayed from a neuron to a postsynaptic cell. Include the synapse, neurotransmitter, degrader, EPSP, and IPSP.

• Neurotransmitter released from presynaptic terminal binds to postsynaptic receptors.

• Synapse may be excitatory (EPSP) or inhibitory (IPSP).

• Neurotransmitter degradation by enzymes like acetylcholinesterase terminates signal .

What are the 3 different types of postsynaptic cells?

Other neurons, muscle cells, and gland cells

List characteristics of the following neurotransmitters: acetylcholine?

Stimulates muscle contraction, degraded by acetylcholinesterase.

List characteristics of the following neurotransmitters Acetylcholineesterase?

List characteristics of the following neurotransmitter: dopamine?

Temporary Pleasure, regulates skeletal tone

List characteristics of the following neurotransmitter: Norepinephrine?

Alertness, fight or flight response, sympathetic division, same things as adrenaline

List characteristics of the following neurotransmitter: GABA?

Most common inhibitory neurotransmitter protein

List characteristics of the following neurotransmitter: Endorphins.

Natural pain relief “feel good” ur body’s own medicine

List characteristics of the following neurotransmitter: Serotonin?

while similar to dopamine, creates a long-lasting feeling of happiness or well-being

What are the grouping of cell bodies and axons in the peripheral nervous system:

Cell body: Ganglia

Axon bundles: nerves

Tissue color: Mix of grey matter(bodies) and white matter(axons), depends on location

What are the grouping of cell bodies and axons in the central nervous system:

Cell body: Nuclei

Axon bundles: Tracts

Tissue color: Gray matter (bodies), White matter (axons)

The brain, brain stem and spinal cord contain…

Gray and white matter

White matter…

is unique in that is mostly contains myelinated axons

Gray matter….

is unique in that is mostly contains cell bodies and pretty much everything else