Chapters 13-20 of Anatomy and Physiology

What is the role of epimysium?

Surrounds the entire muscle

What is a circular muscle?

Forms rings around body openings

What do spinal nerves innervate?

Muscles below the neck

What are somatic motor neurons?

Nerve cells serving skeletal muscles

What are muscle cells known as?

Muscle fibers (myofibers)

When does VO2 max typically peak?

Around age 20

What is a myogram?

A chart of muscle contraction timing

What are dendrites?

Branches that receive signals from other neurons

What do oligodendrocytes do?

Form myelin sheaths in CNS

What is the threshold for action potential?

About -55 mV

How many skeletal muscles does the human body have?

Over 600

What connects muscle to bone?

Tendons

What does muscle movement include?

Moving body parts and contents

What is the specialized major function of muscle tissue?

Convert chemical energy in ATP into mechanical energy

What is the significance of muscle architecture?

It relates to muscle strength and function

What percentage of body weight do muscles constitute?

About half

What are the three types of muscle tissue?

Skeletal muscle, Smooth muscle, Cardiac muscle

What is the major function of muscle tissue?

Convert chemical energy in ATP into mechanical energy

What is an example of a muscle name?

Depressor labii inferioris

How are muscles typically named?

Using Latin names based on function or location

What are the universal characteristics of muscle tissue?

Excitability (responsiveness), Conductivity, Contractility, Extensibility, Elasticity

What does excitability in muscle tissue refer to?

Responsiveness to chemical signals and stimuli

What is the study of the muscular system called?

Myology

What are antigravity muscles responsible for?

Preventing us from falling over

What is the role of sphincters in muscle function?

Control the movement of materials within the body

What does perimysium wrap around?

Fascicles of muscle fibers

What are the functions of muscles?

Movement, Stability, Control of openings, Heat production, Glycemic control

How do muscles help with glycemic control?

By absorbing and storing glucose

How do muscles contribute to stability?

By maintaining posture and preventing unwanted movements

How much heat do muscles produce?

Up to 85% of the body's heat

What does contractility mean in muscle tissue?

Muscle fibers shorten when stimulated

What is conductivity in muscle tissue?

Local electrical excitation travels along the muscle fiber

What is extensibility in muscle tissue?

Capability of being stretched between contractions

What does elasticity refer to in muscle tissue?

Returns to original length after being stretched

What are the connective tissues of muscles?

Endomysium: around each fiber, Perimysium: wraps fascicles, Epimysium: surrounds entire muscle, Fascia: separates muscle groups

What is the function of endomysium?

It allows room for capillaries and nerve fibers

Why is knowing innervation important?

It enables diagnosis of nerve injuries

What are the common arrangements of muscle fibers?

Fusiform: thick in the middle, Parallel: uniform width, Triangular (convergent): broad to narrow, Pennate: feather-shaped, Circular (sphincters): form rings

What is compartment syndrome?

Pressure builds within a muscle compartment

What is fascia in muscle structure?

Sheet of connective tissue separating muscles

What are the types of pennate muscles?

Unipennate, bipennate, multipennate

What is a muscle compartment?

A group of functionally related muscles enclosed by fascia

What happens in compartment syndrome?

Blood and fluid accumulate within a compartment

What is the treatment for compartment syndrome?

Rest, immobilization, fasciotomy

What does innervation of a muscle refer to?

Identity of the nerve that stimulates it

How do cranial nerves differ from spinal nerves?

Cranial nerves innervate head and neck muscles

What happens to blood supply during heavy exercise?

Muscular system's share rises to over three-quarters

What characterizes parallel muscles?

Uniform width and parallel fascicles

What is a fusiform muscle?

Thick in the middle and tapered at each end

What is a retinaculum?

A connective tissue band for tendons

What happens if nerve connections to muscle are severed?

Muscle becomes paralyzed

What is muscle innervation?

Identity of the nerve that stimulates a muscle

How many cranial nerves are there?

Twelve (CN I to CN XII)

What is the blood supply to the muscular system at rest?

24 L per minute

What are the major proteins of a muscle fiber?

Myosin: thick filament, Actin: thin filament, Tropomyosin: blocks active sites, Troponin: binds calcium, Titin: stabilizes thick filaments, Dystrophin: links actin to membrane

What is the sarcolemma?

Plasma membrane of a muscle fiber

What are myofibrils?

Long protein cords in muscle fibers

What is glycogen's role in muscle fibers?

Stored energy for exercise

What role do satellite cells play?

Regeneration of damaged muscle tissue

What is the function of T tubules?

Penetrate muscle fiber and transmit signals

What do thick filaments consist of?

Myosin molecules

What role does calcium play in muscle contraction?

Calcium binds to troponin, exposing active sites

What is the power stroke in muscle contraction?

Myosin head pulls thin filament during contraction

What does an antagonist do?

Opposes the prime mover's action

What are A-bands in muscle striations?

Dark bands where thick filaments overlap

What is a sarcomere?

Segment from Z disc to Z disc

What are I-bands in muscle striations?

Light bands with only thin filaments

What happens during relaxation phase of a muscle twitch?

Tension declines to baseline

What factors influence the strength of muscle twitches?

The muscle's starting length

What is fatigue in muscle physiology?

Progressive weakness from prolonged use

How does ATTP supply affect muscle contraction?

Oxygen and organic energy sources influence ATP supply

What are the physiological classes of muscle fibers?

Slow-twitch, fast-twitch, intermediate fibers

What are the major subdivisions of the nervous system?

Central and peripheral nervous systems

What is a nerve?

A bundle of nerve fibers wrapped in tissue

What is the function of the central nervous system?

To coordinate and control body functions

What do sensory (afferent) neurons do?

Detect stimuli and transmit information

What is the neurosoma?

The control center of a neuron

What is the function of the motor (efferent) division of the PNS?

Carries signals from CNS to effectors

How many axon terminals can a spinal motor neuron have?

About 10,000 axon terminals

What is the role of microglia?

Wander looking for debris and damage

What are the layers of the meninges?

Dura mater, arachnoid mater, pia mater

What is depolarization in action potential?

Change in membrane potential toward zero mV

What are the methods used for nerve regeneration?

Alignment of nerve fibers and minimal damage

What is the function of cerebrospinal fluid (CSF)?

Cushions the brain, provides buoyancy, removes waste products, maintains stable chemical environment

What is the composition of myelin?

20% protein and 80% lipid

What happens during hyperpolarization?

Membrane becomes more negative than resting potential

How is resting membrane potential generated?

Distribution of ions across the membrane

What neurotransmitter produces EPSPs?

Glutamate and aspartate

What is the primary role of the cerebellum?

Coordination and balance

What does presynaptic inhibition do?

Suppresses neurotransmitter release

What happens during the absolute refractory period?

No stimulus can trigger an action potential.

How does the blood-brain barrier protect the brain?

Protects blood capillaries throughout brain tissue.

How does the autonomic nervous system affect heart rate?

It can increase or decrease heart rate.

What are circumventricular organs (CVOs)?

Places where the blood-brain barrier is absent.

What are the key functions of the brainstem?

Controls basic life functions, connects cerebrum and spinal cord, regulates heart rate and breathing.

What is the function of the hypothalamus?

Maintains homeostasis and regulates various functions.

How is information integrated in neurons?

By summation of postsynaptic potentials.

What is the primary function of the occipital lobe?

Responsible for vision.

What happens if blood flow to the brain is interrupted?

Loss of consciousness, significant impairment of neural function, irreversible damage.

What is the role of the pyramids in the medulla oblongata?

Crossing of motor messages to opposite sides.