HHP 2654 Applied Anatomy Exam 2 Muscles and Nerves Oklahoma State Professor Bert H. Jacobson

Where do you find smooth muscle?

In the walls of hollow organs, blood vessels, lymphatic vessels, the bladder, and the uterus

What is an intercalated disc?

cross-bands that separate the opposing ends of cardiac muscle cells. These bands are the result of elaborate junctions of membranes at the cell's boundary. They help to hold adjacent cells together and transmit the force of contraction from cell to cell.

Most abundant substance in muscle

Connective Tissue ?

What is muscle extensibility?

the capability of being stretched

What type of contraction when muscle lengthens?

Eccentric contraction

What is a myoblast?

a type of embryonic progenitor cell that differentiates to give rise to muscle cells. Skeletal muscle fibers are made when myoblasts fuse together; muscle fibers therefore have multiple nuclei (each nucleus originating from a single myoblast).

What is epimysium?

The outer most connective tissue

What is perimysium?

Dense regular connective tissue around the fascicle (bundle) of fibers

What is endomysium?

Dense regular connective tissue around a single muscle fiber

What is a fascicle?

is any cluster or bundle, but the term is most commonly used to describe bundles of muscle or nerve fibers.

Where do you find the neurovascular bundle?

Found in the perimysium

What is sacrolemma?

The fundamental unit of muscle

What are the 2 muscle proteins?

actin and myosin. What they do is they slide past each other and that makes a muscle cell work.

What does a muscle cell contain?

Cardiomyocytes show striations similar to those on skeletal muscle cells, but unlike multinucleated skeletal cells, they contain only one nucleus. Cardiomyocytes have a high mitochondrial density, which allows them to produce adenosine triphosphate (ATP) quickly, making them highly resistant to fatigue.

Actin

thin

Myosin

thick

Types of Muscle Tissue

Cardiac

Smooth

Skeletal

Cardiac Muscle Tissue

Only found in the wall of the heart this tissues contractions are involuntary. They are usually a single nucleus and join to another muscle call at an intercalated disc.

Smooth Muscle Tissue

Found in the walls of hollow organs, blood vessels, lymphatic vessels, the bladder, and the uterus this tissue lacks striations and its contractions are involuntary. They are single nucleus spindle shaped cells.

Skeletal Muscle Tissue

Attached to and move the skeleton this tissue is striated and multinucleate. This tissue functions as a guard of entrances and exits of the body and a support for soft tissue. It also plays a role in the maintenance of body temperature.

Excitability

receive and respond to stimulace

Contractibility

change shape as a result of stimuli (becomes shorter and thicker)

Extensibility

may be stretched beyond normal length

Elasticity

readily returns to normal length after stretch

Concentric

muscle shortens overcoming resistance (positive)

Eccentric

tension in the muscle while it is lengthening. Resistance to overcome tension (negative)

Static

tension in the muscle but no movement

Effects of Training

- increase in myofilament size especially myosin

- increase in mitochondria

- increase in number and size of myofibrils

- increase in reticular systems volume

- increase in capillaries (size and number)

- increase in size of connective tissues

- reduction in fat

Muscle as Body Mass Percentage

Average Adult Male - 42% skeletal muscle

Average Adult Female - 36% skeletal muscle

Muscle fibers can only develop ______ and _________

tension, relax

Motion is only possible if tension _______resistance or if __________ overcomes tension

overcomes, tension

When a muscle fiber contracts it will contract __________

Maximally ( All or Nothing )

Muscle Anatomy

75% water

20% protein

2% fat

1% CHO

Skeletal Muscle

- striated tissue controlled by the somatic nervous system

- most are attached to muscle by tendons

- 75 pairs involved with posture and movement

Hypertrophy

increased muscle size

Atrophy

muscle fibers became weaker and smaller

Skeletal muscles form by fusion of mononucleated ______ to form multinucleated myotubes

Myoblasts

Muscle fibers develop through the fusion of mesodermal cells called _______

Myoblasts

Sarcomere

functional and structural unit of the muscle cell; smallest contractile element of a muscle; segment of a myofibril; extends from one z line to the next

Neuron

A nerve cell; the fundamental unit of the nervous system, having structure and properties that allow it to conduct signals by taking advantage of the electrical charge across its cell membrane.

Mitocondria

________ is powerhouse of the cell and uses glucosse to make energy (ATP)

Agonist Muscle

The muscle that is directly responsible for the movement at a joint. (IE the prime mover)

Antagonist Muscle

A muscle that works in opposition to the specific movement generated by the agonist and is responsible for returning a limb to its initial position.

Isotonic

Proprioceptors

Sensory receptors, located in the muscles and joints, that provide information about body position and movement.

Type 1 muscle fibers

slow twitch, slow oxidative, dependant on oxidative metabolism and lipids for fuel (red in color)

Type 2A muscle fibers

fast twitch oxidative glycolytic (FOG) - FR - fatigue resistance

Type 2B muscle fibers

fast twitch; found in arms, shoulders and legs, fatigue faster

What makes muscle fibers red?

myoglobin

What factors can increase protein synthesis in muscles?

resistance training, steroids, stretching

What is a motor unit?

The functional unit of movement consisting of the anterior motor neuron and the specific muscle fibers it innervates.

Sarcopenia

Loss of muscle mass and strength associated with aging.

Resting Potential

The difference in electric charge between the inside and outside of a neuron's cell membrane

Acting Potential

An impulse in a neuron taking the form of a wave of depolarization or hyper-polarization.

Refractory Period

The time after a neuron fires or a muscle fiber contracts during which a stimulus will not evoke a response

Embryonic cell that builds muscle

myoblast

Stabilizer Muscle

a muscle that steadies or holds a body part in place. It anchors the bone so that the prime mover has a firm base against which to contract, i.e., for the muscle to pull against. Stabilization is very important in all movements in order to have precise movements of the limb or body part.

Synergist

A muscle functioning in cooperation with another muscle

Isotonic Muscle Contraction

Developing tension and producing both concentric and eccentric contractions

Isokinetic Muscle Contraction

Developing tension in the muscle but only in the concentric phase

Isometric Muscle Contraction

Developing tension but no movement

Co-contraction

Contraction of both agonist and antagonist with no movement

Terminal Cistern

Area surrounding the t-tubes that stores Ca++

What will happen to a muscle with the presence of ATP?

contraction

Efferent Nerves

carry nerve impulses away from the central nervous system to effectors such as muscles or glands

The herpes virus is transported along nerves the skin then to the dorsal ganglion where it becomes latent and resides in the ____________

Neuron

DOMS

Delayed Onset Muscular Soreness

Myofibrillar Hypertrophy

The increase in size of muscle cells (myofibrils).

Sarcoplasmic Hypertrophy

An increase in muscle size due to an increase in the volume of sarcoplasmic fluid as a result of high-repetition weight-lifting sets.

In what three times in life are fat cell hyperplasia possible?

Birth, puberty, and .....

Fusiform Muscles

Fascicles are parellel to the direction of the muscle. They are weak but shorten to 1/3 or 1/2 length. Good for speed not force

Penniform Muscles

fibers run diagonally w/ respect to a tendon running through a muscle. Feather shaped, short fascicles, run at angles. Fiber force in a different direction then the muscle force. Change in the individual fiber length is not equal to the change in muscle length. High force, power producing.

Multipenniform Muscles

Several tendons are present with fbers running diagonally between them