Chapter 2 The Muscular System

Cardiac muscle

Pumps blood though heart Major Location: Walls of the heart

Structure of Skeletal Muscles

Skeletal muscles are the major organs that make up the muscular system. Connective tissue coverings are associated with skeletal muscles. Fascia, Tendon, Aponeurosis, Epimysium, Perimysium, Endomysium

5) Perimysium

THis connective tissue divides a muscle into section called facicles.

Types of Muscle Tissue

There are three types of muscle tissue: skeletal, smooth, and cardiac

Attachments and Actions of Skeletal Muscles

There are two types of attachments for skeletal muxcles known as orgins and insertions.

Intercalated discl

These allow the fibers in that group to contact and relax together.. Cardiac muscle is also self - exciting, which means that it does not need nerve stimulationg to contract.

6) Endomysium

This covering of connective tissue surrounds individual muscle cells.

1) Fascia

This structure covers entire skeletal muscles and separates them from each other.

4) Epimysium

This tissue is a thin cobering that is just deep to the facia of a muscle. It surronds te entire muscle.

2) Tendon

This tough cord-like structure is made of fibrous connective tissue that connects muscles to bones

3) Aponeurosis

This tough sheet-like structure is made of fibrous connective tissue. It typically attaches muscles to other muscles

Smooth Muscle

Two types of smooth muscke - multiunit and visceral

Functions of the Muscle

allows muscles to perform various function. In addition to allowing the human body to move, muscles provide stability, the control of body openings and passages, and warming of the body.

Skeletal muscles

are attached to bnes by tendons

Production of Energy for Muscle

because a lot ofr ATP (adenosine triphosphate), which is a type of chemical energy. There are three ways through which muscle cells make energy. Creatine phosphate, Aerobic respiration Lactic acid

Muscle cells or myocytes are called muscle fibers

because of their long lengths.

Flexion

bending a body part or decreasing the angle of a joint

Acetylcholinesterase

breaks down acetylcholine. This allow the muscle to relax.

Acetycholine

causes skeletal muscle to contract. Once contraction has occurred skeletal muscles release an enzyme called acetylcholinesterase.

Visceral smooth muscle

contains sheets of muscle cells that closely contact each other. It is found in the walls of hoolow organs such as stomach, intestines, bladder, and uterus.This type of muscle produces an action called peristalsis

Hyperextension

extendiong a body part past the mormal anatomical position.

Muscle Fatigue

is a condition in which a muscle has lost its ability to contract. It usually develops because of an accumulation of lactic acid. Cramps which are painful, involuntary contractions of muscles can accompany muscle fatigue.

Antagonist

is a muscle that produces a movement opposite to the prime mover. The antagonist is the triceps brachii because its action is to extend the arm at the elbow. While the prime mover and synergists contract, the agonist relaxes; when the antagonist contreacts the prime mover and synergists relax.

Peristalsis

is a rhythmic contraction that pushes substances through tubes of the body.

Insertion

is an attachment site for more moveable bone during muscle contraction.

Origin

is an attachment site for the less moveable bone during muscle contraction

Multiunit smooth muscle

is found in the iris of the eye and the walls of blood vessel. This muscle type contract in response to neurotransmitters and hormones.

Smooth muscle

moves contents though organs; vasoconstriction Major Location Walls of hollow organs, blood vessels and iris

Abduction

moving a body part away from the midline of the body

Circumduction

moving a body part in a circle for example moving your arm in a circular motion

Adduction

moving a body part toward the midline of the body.

Control of Body Openings and Passages

muscles also form valve like structures called sphincters around various body openings and passages. These sphincters control the movement of substances into and out of these passages. Example: a urethral sphincter prevents urination until you relax it to permit urination

3) Lactic acid production

occurs when a cell is low in oxygen and must convert pyruvic acid to lactic acid. This conversion produces a small amount of ATP for the cell, but because lactic acid is a waste product, it must then be released from the cell.

Extension

straightening a body part or increasing the angle of a joint

sarcolemma

the cell membrane of a muscle fiber the cytoplasm of this cell is called sarcoplasm, and the endoplasmic reticulum is called sarcoplasmic reticulum. Most of thesaroplasm is fille with long structures called myofibrils. The arrangement of filaments in myofibrils produce the striations observed in skeletal and cardiac muscle cells. Muscles fibers are controlled by motor neurons that release neurotransmitters onto the fibers.

Pronation

turning the palm of the hand down or lying face down

Supination

turning the palm of the hand up or lying face up

Inversion

turning the sole of the foot medially

Rotation

twisting a body part for example truning your head from side to side

2) Aerobic repiration

uses the body's store of glucose to make ATP. A cell breaks down glucose into pyruvic acid using oxygen (hence the term aerobic). Thepyruvic acid is further conberted into acetly coenzyme A, which begins a series of reactions known as Krebs cycle or the citric acid cycle. The oxygen needed for this method is stored in the muscle pigment called myoglobin, which also gives muscle its pinkish color.

Heat Production

when muscles contract, heat is released, which helps the body maintain a normal temperature. This is why moving your body can make you warmer if you are cold.

1) Creatine phosphate production

Creatione phosphate productionis a rapid way for muscle to produce energy. When ATP is used during muscle contraction, it loses a phosphae and, therefore energy. Creatine phosphate "donates" a phosphate group, restoing energy potential.

Cardiac Muscle

Groups of cardiad muscle are connected to each other through intercalated discs.

Oxygen Debt

occurs when skeletal muscle is used strenuously for several minutes. When pyruvic acid is converted to lactic acid for energy production, the lactic acid builds up muscle fatgue. The lactic acid is brought to the liver via the bloodstream to be convertedback into glucose, which requires more energy. The amount of oxygen the liver cells need to make enough ATP for this conversion results in the oxyger debt.. This process explains why your body still burns energy even after you are done exercising.

Plantar flexion

pointing the toes down

Dorsiflextion

pointing the toes up

Skeletal muscle

produces body movements and facial expressions Major Location: Attached to bones and skin of the face

Prime movers or agonist

responsible for most of the movement. Other muscles help the prime mover by stabilizing joints, and thers muscles are called synergists.

Skeletal Muscle

skeletal muscle fibers respond only to the neurotransmitter acetylcholne