Muscular System - Final

Fibrous Joint

Bones that are united by fibrous tissue

Ex: Sutures of the skull

Cartilaginous Joint

Bones that are connected by cartilage

Ex: Pubic symphysis

Synovial Joint

Articulating bones have a space (synovial cavity) between them.

Articulating Bone

The two(or more) bones that meet to form the joint

Articulating cartilage

The smooth, white tissue covering the ends of the ones to reduce friction.

Synovial Membrane

The inner lining of the capsule that secretes the “grease” for the joint

Synovial Fluid

The egg white like liquid that fills the cavity and lubricates movement

Articular capsule

The “envelope” surrounding the joint, made of an outer fibrous layer and the layer and the inner membrane

Collateral Ligaments

Strong bands of connective tissue located outside the capsule that prevent side to side instability

Ball and Socket joint

Ball-like surface of one bone fits who the cuplike depression of another bone

Ex: hip joints

Hinge joint

Permits flexion and extension only

Ex: elbow

Saddle joint

The articular surface of one bone is saddle shaped and the articular surface of the other bone fits into

Ex: Thumb joint

Condyloid joint

Reduced ball and socket joint

Ex: metacarpals

Pivot joint

Allows for rotation

Ex: between atlas and axis

Planar joint

Bones move on a flat or slightly curved surface

Ex: Tarsals

Extension

Increase the angle at the joint

Ex: straightening the knee

Flexion

Decreases the angle at a joint

Ex: Bending the knee of elbow

Dorsiflexion

Standing on heels of foot

Plantarflexion

Standing on toes

Adduction

bringing the limbs toward the midline

Abduction

bringing the limbs away from the midline

Circumduction

Turning the arms in a circle

Rotation

Movement around the axis

Ex: Shaking head no

Supination

Movement so that the plans face up like in anatomical position

Pronation

Moving the palms so they face now. The radius crosses the ulna

Inversion

Turning sole in toward midline

Eversion

Turning sole outward away from midline

What are the functions of the muscular system (Get Some Muscles Please!)

Generated heat

stabilizes joints

Maintains posture

Produces movement (with skeletal system)

Is skeletal muscle straited or nonstraited, voluntary or nonvolunatry, Multinucleated or uninucleated, and location

It is straited, volunatary, multinucleated, and attached to bone

Is Smooth muscle straited or nonstraited, voluntary or involunatry, Multinucleated or uninucleated, and location

It is unstraited, involuntary, uninucleated, and lines the internal organs

Is cardiac muscle straited or nonstraited, voluntary or involunatry, Multinucleated or uninucleated, and location

It is straited, involuntary, uninucleated, and the heart

What are intercalated discs and what muscle tissue type are they found in?

They join the branching cells in cardiac muscle so the muscle acts as one unit. They are found on the heart

Origin

Point of attachment of muscle on immovable or less moveable bone

Insertion

Point of attachment of muscle on the more moveable bone

Prime mover

Muscles that provide the primary force for movement

Synergist

Muscles that help the prime movers by producing the same movement

Antagonist

Muscles that oppose a movement

Fixator

Muscles that stabilize the origin of the prime movers

Location

Relative to a bone region

Ex: temporalis

Action

Movement that muscle performs

Ex: Adductors

Direction

In which muscle fibers run

Ex: External oblique

Shape

Of the muscle

Ex: Trapezius

Number of origins

How many origins

Ex: biceps brachii

Origin & insertion

Location where muscles attaches

Ex: Sternocleidomastoid

Relative size

Of the muscle

Ex: Gluetus Maximus

Used in smiling

Zygomaticus

Used to suck in you cheeks

Buccinator

used in winking

Orbicularis oculi

Used to form the horizontal frown crease on the forehead

Frontalis

The “kissing” muscle

Orbicularis oris

Prime mover of jaw closure

masseter

Synergist muscle for jaw closure

Temporalis

Prime mover of head flexion: two-headed muscle

Sternocleidomastoid

Epimysium - Connective tissue layer

Covers entire muscle

Perimysium - ct layer

Surrounds fascicle

Endomysium - ct layer

Wraps individual muscle fibers

Fascicle

Bundle of muscle

Sarcolemma

Plasma membrane surrounding each muscle fiber

Sarcoplasm

Cytoplasm of the muscle cell

Myofibril

Inside muscle cells and is composed of myofilaments

Myofilament

Actin and myosin

Sarcomere

Contractile unit of muscle

Sliding Filament theory

Myosin heads pull on the actin causing the thin filaments to slide toward the center of the sarcomere. The filaments don’t change in length, the sarcomere shortens as the filaments overlap.

What happens to the I band and H zone

THe I band gets smaller and the H zone disappears

Motor unit

A neuron and all of the muscle cells it stimulates

What happens at the NMJ

Nerve impulses cause release of neurotransmitter Acj which is a chemical message sent across the synaptic cleft to the sarcolemma. This triggers a chain reaction, leading to muscle contraction.

How does Botox work

It blocks the release of neurotransmitter ach and temporarily paralyzes the muscle

The characteristic of muscle tissue that describes its ability to receive and respond to a stimulus is

excitability

Which muscles extends the forearm

Triceps Brachii

The “tailor muscle” that adducts the thigh/hip (crosses the legs")

sartorius

What is the muscle that is the prime mover for jaw closure

masseter

What muscle retracts and elevated the mandible and helps to close the jaw. It is the synergist to the masseter

Temporalis

What characteristic of muscle tissue allows it to return to its original size/shape after stretching

Elasticity

The ability of a muscle call to shorten in length

contractility

The ability of a muscle cells to stretch

Extensibility

T thick band of dense ct that forms most connections between muscle and bone

tendon

myofibrils

tiny fibers that run parallel along the entire length of the muscle cell

What does botulism poisoning do

it causes muscle paralysis because it blocks the release of ach from the axon terminal of the neuron so the muscle never gets the message to contract.

Skeletal muscle fiber contraction order

1. Ach is release from axon terminal

2. Action potential travels into T (Transverse) tubules

3. Sarcoplasmic reticulum releases calcium

4. Calcium combines with troponin

5. Energized myosin heads attach to active

What is the process of skeletal muscle fiber contraction order

Due to a nerve impulse, ACH is released from the axon terminal to the synaptic cleft to the sarcolema. From there, it binds and then we have action potential that travels down the transverse tubules. Then the sarcoplasmic reticulum relseases calcium that then binds with troponin so the troponin/tropomyosin complex binding sites on actin are exposed with the help of split ATP the myosin heads are now able to attach to actin creating a cross bridge and allowing for the powerstroke. The heads are able to attach because troponin/tripomyosin are not blocking the sites becayse troponin binded with calcium. For the heads to detach more ATP is needed and the myosin will recharge until the next contraction. The powerstroke is the myosin heads pulling actin filaments inward toward the sarcomere’s center (M-line).