A&P 1 Exam 4: Chapter 10, 11, and 12

Define anaerobic endurance

(50-meter dash, weight lifting) Fast fibers and stimulates hypertrophy Improved by frequent, brief, intensive workouts

Describe the location, structure and function of microglia

(macrophage) Smallest and least numerous neuroglia Have many fine-branched processes Migrate through nervous tissue Clean up cellular debris, wastes, and pathogens

Describe the location, structure, and function of Schwann cells

(neurolemmocytes) form myelin sheath or indented folds of plasma membrane around axons A myelinating Schwann cell sheaths only one axon; Many schwann cells sheath entire axon

Define aerobic endurance

(prolonged activities) Supported by mitochondria No muscle hypertrophy Training involves sustained, low levels of activity Alterations characteristics of muscle fibers Cardiovascular performance

Describe the structural classification of neurons. Where you would find them: unipolar

(pseudounipolar neurons) Axon and dendrites are fused; Cell body to one side most sensory neurons of PNS

What is Wallerian degeneration

-Axon distal to injury degenerates -Schwann cells forms path for new growth, wraps new axon

Neuron

A cell in nervous tissue that is specialized for intercellular communication through (1) changes in membrane potential and (2) synaptic connections

Ganglion

A collection of neuron cell bodies in the peripheral nervous system

What is a myogram? Give a brief description of the 3 phases.

A graphic representation, showing tension development in muscle fibers from various skeletal muscles. 3 phases: The latent period: begins at stimulation and lasts about 2 msec. During this period, the action potential sweeps across the sarcolemma, and the SR releases calcium ions. The muscle fiber does not produce tension during the latent period, because the contraction cycle has yet to begin. The contraction phase: tension increases , calcium ions are binding to troponin, active sites on thin filaments are being exposed, and cross-bridge interactions are occurring. For this muscle fiber, the contraction phase ends roughly 15 msec after simulation. The relaxation phase: lasts about 25 msec. During this period, the Ca2+ level is decreasing as calcium ions are pumped back into the SR, active sites are being covered by tropomyosin, and the number of active cross-bridges is declining as they detach. As a result, tension decreases to the resting level.

Define eccentric isotonic muscle contractions

A muscular contraction in which the muscle lengthens Example: Lowering phase of a biceps curl

action potential

A propagated change in the membrane potential of excitable cells, initiated by a change in the membrane permeability to sodium ions

Dendrites

A sensory process of a neuron

Propagation - saltatory

A special type of propagation for the action potential

Nerves

A whitih fiber or bundle of fibers that transmits impulses of sensation to the brain or spinal cord, and impulses from these to the muscles and organs

What is the significance of a sarcomere

Able to initiate large, sweeping movement by contracting in unison. Allows these tiny units to coordinate our muscles' contractions

Propagation - Continuous

Action potentials along an unmyelinated axon

Function of myosin

After cross-bridge formation, the energy that was stored in the resting state is released as the myosin head pivots toward the M line. This action is called the power stroke; when it occurs, the bound ADP and phosphate group are released. Located in the M line of the sarcomere.

Describe the following types of channels in plasma membranes: passive channels (leak channels)

Are always open Permeability changes with conditions

Function: troponin

Binds tropomyosin, G-actin, and Ca2+

How do the following affect muscle contraction: botulism

Blocks release of ACh Results flaccid paralysis

Describe the components of CNS (afferent and efferent divisions), and the general function

Brain and spinal cord Nervous tissue, connective tissue, and blood vessels Functions to process and coordinate sensory data from inside and outside the body Motor commands control activities of peripheral organs (ex: skeletal muscles) Higher functions of brain include intelligence, memory, learning, and emotion

Describe the location, structure, and function of these parts of a multipolar neuron: collaterals

Branches of the axon

Structure, function, and location: tendon

Tough, rounded cord-like structures which are extensions of the muscle. Allow attachment of the muscle from its originating bone to the bone on which it ends

What is the basic function of the somatic nervous system

Controls skeletal muscle contractions Both voluntary and involuntary (reflexes)

What is the basic function of the autonomic nervous system

Controls subconscious actions, contractions of smooth and cardiac muscle, and glandular secretions

Function: Tropomyosin

Covers active sites on G-actin; Prevents actin-myosin interaction

How do the following affect muscle contraction: Parkinson's disease

Damage/degeneration of substantia nigra Dopamine producing neurons Usually after 50, more in men, can be genetic

What is saltatory conduction, include how and why it occurs, and how it affects the speed of impulse conduction

Describes the way an electrical impulse skips from node to node down the full length of an axon, speeding the arrival of the impulse at the nerve terminal in comparison with the slower continuous progression of depolarization spreading down and unmyelinated axon.

Function: nebulin

Holds F-actin strand together

Describe the location, structure and function of ependymal cells

Epithelium that lines central canal of spinal cord and ventricles of brain. Produce and monitor cerebrospinal fluid (CSF) Have cilia that help circulate CSF

location, structure, and function: T tubules

Extend from surface of muscle fiber deep into sarcoplasm Transmit action potentials (trigger contraction) from sarcolemma into cell.

Structure, function and location: aponeurosis

Extremely delicate, thin sheath-like structure which attaches muscles to the bones

Function: Actin (include Active Site)

Found in both the cytoplasm and the cell nucleus. Active site is usually a groove or pocket of the enzyme which can be located in a deep tunnel within the enzyme, or between the interfaces of multimeric enzymes.

What is myoglobin and why is it necessary in skeletal muscle

Found in your heart and skeletal muscles. There it captures oxygen that muscle cells use for energy.

Describe the generation of an action potential including the events at the cholinergic synapse of a skeletal muscle

Generated by special types of voltage-gated ion channels embedded in a cell's plasma membrane. When the channels open, they allow an inward flow of sodium ions, which changes the electrochemical gradient, which in turn produces a further rise in the membrane potential towards zero

Describe the structural classification of neurons. Where you would find them: multipolar

Have one long axon and two or more dendrites Common in the CNS All motor neurons that control skeletal muscles

Describe the second messenger response for neurotransmitters. What is the biomedical significance?

Intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules. Trigger physiological changes at cellular level such as proliferation, differentiation, migration, survival, apoptosis and depolarization.

fasciculation

a brief, spontaneous contraction affecting a small number of muscle fibers; often causing a flicker of movement under the skin.

neurotransmitter

a chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and by diffusing across the synapse or junction

Describe oxygen debt

a cumulative deficit of oxygen available for oxidative metabolism that develops during periods of intense bodily activity and must be made good when the body returns to rest.

Glycolysis

a cytoplasmic pathway which breaks down glucose into two three-carbon compounds

neuromuscular junction

a highly specialized synapse between a motor neuron nerve terminal and its muscle fiber

Define tension load (resistance)

a passive force that opposes movement. The amount of load can depend on the weight of the object, its shape, friction, and other factors. When the applied tension exceeds the load, the object moves.

Excitability

a property of a cell, allowing it to respond to stimulation by rapid changes in membrane potential produced by ion fluxes across the plasma membrane

Describe the location, structure and function of astrocytes

Large cell bodies with many processes Function to maintain blood brain barrier (BBB), Create three-dimensional framework for CNS, Repair damaged nervous tissue, Guide neuron development, and Control interstitial environment

Structure, function and location: epimysium

Layer of collagen fibers surrounds muscles Connected to deep fascia Separates muscle from surrounding tissues

Structure, function, and location: myofibril

Lengthwise subdivisions Responsible for muscle contraction bundles of protein filaments Two types: Thin filaments (actin) and Thick filaments (myosin)

Describe the location, structure, and function of these parts of a multipolar neuron: axon hillock

Located at the end of the soma and controls the firing of the neuron

Function: Titin

Located in the I band. Elastic protein Extends from tips of thick filaments to the Z line Keeps filaments in proper alignment Aids in restoring resting sarcomere length

describe the location, structure and function of synaptic vesicles

Located in the axon terminal Contain monotopic and polytopic proteins as well as associated membrane proteins, including synapsins, cysteine string protein (CSP) and rab proteins. Involved in synaptic functions such as uptake, storage and stimulus-dependent release of neurotransmitter

Describe the location, structure and function of the motor end plate

Located in the neuromuscular junction. Midpoint of the muscle fiber. Gives rise to very fine processes that run along skeletal muscle cells.

What is muscle fatigue and why does it occur

Muscles can no longer perform at a required level. Depletion of metabolic reserves, damage to sarcolemma and sarcoplasmic reticulum, decline in pH, which affects calcium ion binding and alters enzyme activities, and weariness due to low blood pH and pain

What is the structure and function of the two cell types of the nervous system (NS), and describe the most important "part" of the NS.

Neurons - process information. Glia - provide the neurons with mechanical and metabolic support The most important part is the brain

Spatial summation

Occurs as stimuli are applied simultaneously but in different areas

Explain why neurotransmitters cannot continually stimulate a sarcolemma

Occurs by enzymatic degradation, reuptake into the presynaptic cell, or diffusion

What is the basic sequence for muscle relaxation

Occurs when stimulation of the nerve stops. Calcium is then pumped back into the sarcoplasmic reticulum breaking the link between actin and myosin. Actin and myosin return to their unbound state causing the muscle to relax.

cranial nerves

Peripheral nerves originating at the brain

PNS

Peripheral nervous system

Visceral

Pertaining to viscera (internal organs) or their outer coverings

location, structure, and function: Sarcolemma

Plasma membrane of muscle fiber that surrounds the sarcoplasm Site where calcium enters and leaves the cell through a distribution of ion channels, transporters and pumps.

location, structure, and function: cisternae

Plays a crucial role in the packaging, modification, and transport functions of the cell overall Located in the golgi apparatus

Structure, function and location: muscle

Producing movement Maintaining posture and body position Supporting soft tissues Guarding body entrances and exits Maintaining body temperature Storing nutrients

Describe the location, structure, and function of these parts of a multipolar neuron: neurofibrils

Provide support for dendrites and axon Fibres in the cytoplasm of a nerve axon

White and red muscle

Red muscle fibers are a type of skeletal muscle which are dense with capillaries and is rich in myoglobin and mitochondria. White muscles are also a type of skeletal muscle, but contain lower amounts of myoglobin and mitochondria.

Describe the following types of channels in plasma membranes: voltage gated channels

Respond to changes in membrane potential Axons of neurons and sarcolemma of skeletal and cardiac muscle cells Activation gate opens when stimulated Inactivation gate closes to stop ion movement Three possible states - Closed but capable of opening, open (activated), and closed and incapable of opening (inactivated)

Describe the following types of channels in plasma membranes: mechanically gated channels

Respond to membrane distortion Found in sensory receptors that respond to touch, pressure, or vibration

Describe the location, structure, and function of these parts of a multipolar neuron: dendrites

Short, highly branched processes extending form cell body Receive information from other neurons - 80%-90% of neuron surface area

Structure, function and location: muscle fiber

Single cylindrical muscle cell Help control the physical forces within the body.

Describe the location, structure, and function of these parts of a multipolar neuron: axon (axolemma)

Single, long cytoplasmic process Propagates electrical signals (action potentials) Axoplasm - (cytoplasm of axon) and contains neurofibrils, neurotubules, enzymes, and organelles

Describe the structural classification of neurons. Where you would find them: bipolar

Small and rare; One dendrite and one axon Special sense organs (sight, smell, hearing)

Describe the location, structure, and function of oligodndrocytes

Small cell bodies with few processes Many cooperate to form a myelin sheath

What are the differences between somatic and visceral motor neurons

Somatic motor neurons - Innervate skeletal muscles Visceral motor neurons - Innervate all other peripheral effectors; Smooth and cardiac muscle, glands, adipose tissue

What is the functional difference between somatic sensory neurons and visceral sensor neurons?

Somatic sensory neurons - monitor external environment Visceral sensory neurons - monitor internal environment

Describe the location, structure and function of synaptic cleft.

Space between two neurons, connecting them to one another forming a synapse. Helps nerve impulse pass from one neuron to the other. Located within the small gap between the axon terminal of the presynaptic neuron and the membrane of the postsynaptic cell

Describe the sequence for muscle contraction (sliding filament theory)... beginning with release of the neurotransmitter from synaptic vesciales

The H bands and I bands of the sarcomeres narrow, the zones of overlap widen, the Z lines move closer together, and the width of the A band remains constant. This only makes sense if the thin filaments are sliding toward the center of each sarcomere, alongside the thick filaments. The contraction weakens with the disappearance of the I bands, at which point the Z lines are in contact with the ends of the thick filaments. During contraction, sliding occurs in every sarcomere along the myofibril. As a result, the myofibril gets shorter. Because myofibrils are attached to the sarcolemma at each Z line and at either end of the muscle fiber, when myofibrils get shorter, so does the muscle fiber. If neither end of the myofibril is held in position, both ends move toward the middle. As the muscle fiber contracts, it pulls on the tendon's collagen fibers, which are embedded in the bone. This pulling on the tendon ultimately causes bone movement.

What is the location, function and significance of calsequestrin

The major calcium binding protein in the sarcoplasmic reticulum. Plays a role of calcium storage and a regulator of muscle excitation-contraction coupling and stress responses. Located in heart muscles called myocytes

Describe the Cori cycle

The metabolic pathway in which lactate produced by anaerobic glycolysis in the muscles moves to the liver and is converted to glucose, which then returns to the muscles and is metabolized

Repolorization

The movement of the membrane potential away from a positive value and toward the resting potential

Hyperpolarization

The movement of the membrane potential away from the normal resting potential and farther from 0mV

What two factors improve aerobic endurance

Strength training. Consume carbs Hydrate Choose natural energy boosters

Describe the location, structure, and function of satellite cells

Surround ganglia (clusters of neuronal cell bodies) Regulate interstitial fluid around neurons

Structure, function, and location: endomysium

Surrounds individual muscle cells (muscle fibers) Contains capillary networks, nerve fibers, and myosatellite cells (stem cells) that repair damage

Structure, function and location: fascicle

Surrounds muscle fiber bundles

Structure, function and location: Perimysium

Surrounds muscle fiber bundles (fascicles) Contains collagen fibers, elastic fibers, BV, Nerves

Axolemma

The plasma membrane of an axon, continuous with the plasma membrane of the cell body and dendrites and distinct from any neuroglial coverings

Define Muscle atrophy

The wasting (thinning) or loss of muscle tissue

Can skeletal muscles "push" or compress

They can't push, however they can pull/compress.

Define facilitation

also known as paired-pulse facilitation (PPF), is a phenomenon in neuroscience in which postsynaptic potentials (PSPs) (EPPs or IPSPs) evoked by an impulse are increased when that impulse closely follows a prior impulse.

Creatine

amino acid located mostly in your body's muscles as well as in the brain

Contractility

any increase in the force of contraction (work) that CANNOT be attributed to the Frank-Startling mechanism of the heart

Describe the location, structure, and function of these parts of a multipolar neuron: trigger zone

area of the medulla oblongata that receives inputs from blood-borne drugs or hormones, and communicates with other structures in the vomiting center to initiate vomiting

Describe the structural classification of neurons. Where you would find them: anaxonic

brain/special sense organs Small and all cell processes look similar

Describe the location, structure and function of these parts of a multipolar neuron: perikaryon

cytoplasm

Resting membrane potential

determined by concentration gradients of ions across the membrane and by membrane permeability to each type of ion

Terminal cisternae

enlarged areas of the sarcoplasmic reticulum surrounding the transverse tubules

Define Muscle hypertrophy

enlargement of total muscle mass and cross-sectional area. More common in fast-twitch than in slow-twitch muscles.

slow fibers

fatigue resistant, and focused on sustained, smaller movements and postural control

intermediate fibers

form an elaborate network in the cytoplasm of most cells

How do the following affect muscle contraction: Familial hypertrophic cardiomyopathy

genetic defect in sarcomere Results abnormal contractions and enlarged cardiac muscle

Define concentric isotonic

involves the muscle shortening. The origin an insertion of the muscle move closer together and the muscle becomes fatter. Example: Lifting a heavy weight. Causes the arm to bend at the elbow, lifting the weight towards the shoulder.

How does myelination affect impulse speed

it insulates the axon and assembles voltage-gated sodium channel clusters at discrete nodes along its length

Describe the location, structure, and function of these parts of a multipolar neuron: synaptic knobs

knob-like swellings at the very end of an axon terminal Communicates with a dendrite or cell body of another neuron

Describe the following types of channels in plasma membranes: Chemically gated channels

ligand-gated ion channels Open - bind specific chemicals (e.g., ACh) Cell body and dendrites of neurons

Demyelination

loss of myelin

Twitch

occurs when one muscle fiber contracts in response to a command (stimulus) by the nervous system

Somatic

pertaining to the body

Define isometric

relating to or denoting muscular action in which tension is developed without contraction of the muscle Example: doing a plank or wall sit, the muscles are working, but not actively changing lengths

Parasympathetic division

relaxing effect

Temporal summation

sensory summation that involves the addition of single stimuli over a short period of time

Sympathetic division

stimulating effect

Telodendria

terminal axonal branches that end in axon terminals

Tetanus

tetanospasmin toxin Blocks inhibitory neurotransmitters Results spasms/rigid muscles

Define summation

the additive effect of several electrical impulses on a neuromuscular junction

Muscle tone

the amount of tension (or resistance to movement) in muscles

Define recruitment

the successive activation of the same and additional motor units with increasing strength of voluntary muscle contraction

Myofilaments

threadlike structures that comprise the myofibril inside the muscle cell

Fast fibers

twitch muscle fibers provide bigger and more powerful forces

Somatic nervous system (SNS)

The efferent division of the nervous system that innervates skeletal muscles

Refractory period - relative

The interval of time during which a second action potential can be initiated

What are the three basic functional classifications of neurons, what are their functions

1. Sensory neurons (afferent neurons) - Processes (afferent fibers) extend from sensory receptors to the CNS 2. Motor neurons (efferent neurons) - Carry instructions from the CNS to the peripheral effectors via efferent fibers (axons) 3. Interneurons - Responsible for distribution of sensory information and coordination of motor activity. Involved in higher functions such as memory, planning, and learning.

Refractory period - absolute

The interval of time during which a second action potential cannot be initiated

Define motor unit

All muscle cells controlled by a single motor neuron.

Describe the components of the PNS (afferent and efferent divisions), and the general functions

All nervous tissue outside CNS and ENS Delivers sensory information to the CNS Carries motor commands to the tissues

Describe endurance

Amount of time an activity can be sustained

Define tension

An active force. Energy must be expended to produce it. Applied to some objec, whether a rope, a rubber band, or a book on a tabletop. Applied to an a object teds to pull the object toward the source of the tension.

Describe the location, structure, and function of these parts of a multipolar neuron: synaptic terminals

Axon terminal Tips of telodendria

Efferent division of PNS

Carries motor commands From CNS to muscles, glands, and adipose tissue

Afferent division of PNS

Carries sensory information From receptors in peripheral tissues/organs to CNS

Describe the location, structure and function of these parts of a multipolar neuron: soma

Cell body Large nucleus/nucleolus/mitochondria/RER

Myosatellite cell

Cells that are the precursors to skeletal muscle cells (fibers)

Autonomic nervous system (ANS)

Centers, nuclei, tracts, ganglia, and nerves involved in the unconscious regulation of visceral functions; includes components of the central nervous system and the peripheral nervous system.

CNS

Central Nervous System

What are neurotransmitters, where are they made and how are they transported to outside the neuron

Endogenous - produced inside the neuron itself. When a cell is activated, these neurochemicals are released into the synapse from specialized pouches clustered near the cell membrane

How are the number of motor fibers per motor unit and the quality of control related

If a muscle is required for fine control or for delicate movements, its motor units will tend to have small innervation ratios. That is, each motor neuron will innervate a small number of muscle fibers, enabling many nuances of movement of the entire muscle.

Describe the process of peripheral nerve regeneration

In CNS Limited by astrocytes, which produce scar tissue and release chemicals that block regrowth

Axon hillock

In a multipolar neuron, the portion of the cell body adjacent to the initial segment

location, structure, and function: sarcoplasmic reticulum

Membrane-bound structure found within muscle cells that is similar to the smooth endoplasmic reticulum in other cells

Neurofibrils

Microfibrils in the cytoplasm of a neuron

Neurofilaments

Microfilaments in the cytoplasm of a neuron

Neurotubules

Microtubules in the cytoplasm of a neuron

Define the motor unit.

Motor neuron and all muscle fibers it controls May contain a few muscle fibers or thousands All fibers in a motor unit contract at the same time

Describe nerve myelination, include definition myelin sheath and neurolemma

Much like the insulation around the wires in electrical systems, glial cells form a membraneous sheath surrounding axons called myelin, thereby insulating the axon. This myelination, as it is called, can greatly increase the speed of signals transmitted between neurons Myelin sheath - an insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord. Neurolemma - outer surface of Schwann cell

Myoblasts

Muscle fibers that develop through the fusion of embryonic cells

Spinal nerves

One of 31 pairs of nerves that originate on the spinal cord from anterior and posterior roots

Enteric nervous system (ENS)

One of the three main divisions of the nervous system; it is an extensive nerve network in the walls of the digestive tract that initiates and coordinates digestive motility and secretions

Cell body

The body of a neuron; also called soma

location, structure, and function: sarcoplasm

The cytoplasm of a muscle fibre. Water solution containing ATP and phosphagens, as well as the enzymes and intermediate and product molecules involved in many metabolic reactions. Located within the core of the myotube between and around the nuclei

Perikaryon

The cytoplasm that surrounds the nucleus in the cell body of a neuron

Axoplasm

The cytoplasm within an axon

Axon

The elongated extension of a neuron that conducts an action potential

Treppe

The graduated series of increasingly vigorous contractions that results when a corresponding series of identical stimuli is applied to a rested muscle