Anatomy & Physiology 2-Chamberlain-Chapter 11 and 12 Review

Types of Muscle Tissues

1.Skeletal

2.Cardiac

3.Smooth

Myology

Study of muscles

Functions of Muscular Tissue

-Producing body movements

-Stabilizing body positions

-Storing and mobilizing substances within the body

-Generating heat

Bile

Made in the liver and stored in the gallbladder

Electrical excitability

carry electricity, measured by EKG

Contractility

shortens, creates tension on the bones

Extensibility

stretch beyond normal resting position

Elasticity

goes back to original position

Myoblast

Immature muscle cell

Muscle cells do not…

regenerate

Myocyte

Mature muscle cell

Tendon is infused to the….

muscle sheath

Perimysium surrounds…

fascicule

Calcium is stored in the…

Sarcoplasmic reticulum

Contractile Muscle Protein

-Myosin

-Actin

Regulatory Muscle Protein

-Troponin

-Tropomyosin

Structural Muscle Protein

-Titin

-Nebulin

-Alpha-actin

-Myomesin

-Dystrophin

Actin binding sites bind with…

myosin

80% of titin is on…

membrane protein

Sliding filament mechanism

Actin and myosin changes length

Sliding Filament Mechanism

Myosin pulls on actin causing the thin filament to slide inward Z discs move toward each other and sarcomere shortens, structural proteins make force resulting in whole muscle contraction

Changes in I band and H zone as muscle contracts

H zone is where there is more overlap, the I band gets longer, and the A band does not change (length of myosin)

The distance of sarcomere…

shortens the H zone shrinks because actin-myosin interact sarcomere shortens because of the sequence

The Contraction Cycle:

Fibers get pulled in and we have to energize the head of myosin and add ATP to the binding site. ATP exposes the binding site of actin when crossbridge is formed by calcium. As myosin head binds ATP the crossbridge is formed by calcium. Phosphate releases and power stroke occur. As myosin head binds ATP the crossbridge detaches from actin. Tropmysosin opens the binding site by adding calcium. When electricity goes down the cell membrane, the gates open. Calcium binds with troponin which causes a shift in tropomyosin.

The Neuromuscular Junction:

The electricity goes down the nerve into the end part of the neuron (axon). Every muscle fiber has an end plate. Motor end plates contain a gate. When electricity goes through the gate it allows calcium to go through the nerve. (chemical gate also means Ligands gate)When electricity goes through the gate it allows calcium to go through the nerve. This triggers exocytosis. Sodium rushes in and goes down the transverse tubule. ACH opens Lygand gate. The calcium pump puts calcium back by the ATP pump.

Sodium is on the…

outside

Potassium is on the…

inside

Muscle Metabolism: Creative Phosphate (CP)

Creative kinase catalyzes the transfer

Muscle Metabolism: Anaerobic Glycolysis

When CP stores are depleted, glucose is converted into pyruvic acid

Cellular Respiration

Under aerobic conditions, pyruvic acid can enter the mitochondria and undergo a series of oxygen-requiring reactions to generate large amounts of ATP

Muscle Fatigue

1. Build-up of lactic acid and ADP

2. Depletion of CP, oxygen, and nutrients

3. Inadequate release of Ca+ from SR

4. Insufficient release of ACH at NMJ

CNS

Brain and spinal cord

PNS

Cranial nerves, spinal nerves, enteric plexus in small intestine, sensory receptors in the skin

Somatic Senses

Body

Special Senses

Smell balance, taste

Somatic Nervous system

Skeletal muscle

Sympathetic Nervous System and Parasympathetic Nervous System

Smooth muscles, cardiac muscles, and glands

Enteric Nervous System

Smooth muscle and glands of GI tract

Sensory

1.Sense

2.Motor

3.Intergrative

Sense

Change through sensory receptors

Motor

respond to stimuli

Integrative

Analyze sensory info, store some aspects, make choices based on behavior

Neurons

-Electricity excitable

-Cellular structures

Schwann Cells

Responsible for establishing myelin, oligodendrocytes inside this cell

Satellite Cells

Regulates the exchange of materials inside/outside cells

Myelination of Neurons

The myelin sheath is produced by Schwann cells (PNS) and oligodendrocytes (CNS) and it surrounds the axons of most neurons

More Myelin=

Faster Neuron

Microglial cells

cleans nervous systems

Oligodendrocyte

forms myelin sheath

Ependymal cells

layer of cuboidal cells that contain cilia that regulate the spinal cerebral layer

Astrocytes

gives strength and support, blood/brain barrier, selectively permeable, helps maintain chemical environment for sodium/potassium ions

CNS (4 Types in CNS)

Astrocyte, Oligodendrocyte, Microglial, and Ependymal cells

Neuroglia

-Not electrically excitable

-Make up half the volume of the nervous system

-Can multiply and divide

-6 kinds in total

Neurons can be classified…

by direction of impulse nerve impulse propagation

Functional Classification of Neurons

-Sensory neurons

-Motor/efferent neurons

-Inter/association neurons

How do excitable cells communicate with each other?

Via graded potentials or graded potentials

Action potential (AP)

short and long distances

Graded potential (GP)

allows communication over short distances