Which is not true of skeletal muscle?
a. It enables you to manipulate your enviroment.
b. It influences the body's contours and shape.
c. It is one of the major components of hollow
organs.
d. It provides a means f locomotion.
c. It is one of the major components of hollow organs.
Because the cells of skeletal muscle are relatively large and clindrical in shape, they are also known as__________.
Fibers
Skeletal muscle cells have more than one nucleus.
true/false
True
The two contractile proteins that make up the myofilaments of skeletal muscle are _______and ______.
myosin and actin
Each muscle cell is surrounded by thin connective tissue called the
endomysium
A strong cordlike structure that connects a muscle to another muscle or bone is
a tendon
The junction between a nerve fiber and a muscle cell is called a _______.
neuromuscular junction
The neuron and muscle fiber membranes do not actally touch but are seperated by a fluid-filled gap.
True/False
True
Humans have how many muscles and make up 40% of the body weight.
650
What are the functions of muscle tissue?
movement
posture and body position
stabilize joints
heat generation and protection
What are the special characeritics of muscles?
excitability
contractility
extensibility
elasticity (recoil)
Smooth muscle tissue
is found in the walls of hllow visceral organs such as the stomach, urniary bladder, and respiratory passages.
Motor unit
is a motor neuron and all the muscles it supplies
What is muscle twitch?
is a rapid contraction that is triggered by a single action potential.
Sometimes, we experience muscle twitches around our eyes.
Muscle tone
skeletal muscle s always slightly contracted due to spinal reflexed. It does not produce ative movement. Essential to keep muscles firm, healthy, ready to respond, stablize posture and joints.
In muscle metabolism, muscle fibers can make ATP via three mechanisms:
1. aerobic respiration- requieres O2--slow, but makes the most ATP per molecule of glucose.
2.creatine kinase- does not requiere O2--transfers a phosphate from cretine phosphate to ADP to make ATP.
3. lactic acid fermentation- does not require O2--couples a fermentation step with glycolyis; glucose to latic ad-anerobic-faster than aerobic pathwy but only 5% efficient.
A prime mover or ___________ is responsible for producing a particular type of movement.
agonist
Skeletal muscles are named on the basis of many criteria. Name one?
direction of muscle fibers
True/False
Muscles of acial expression differ from most skeletal muscles because they insert into the skin or other muscles rather than into bone.
True
The _________ musculature includes muscles that move the vertebral colum and muscles that move the ribs.
Trunk
Muscles that act on the _____ cause movement at the hip, knee, and foot joints.
lower limb
This two-headed muscle bulges when the forearm is flexed. It is the most familiar muscle of the anterior humerus. It is the ____.
biceps brachili
These abdominal muscles are responsible for giving me my "six pack". They also stabalize my pelvis when walking. They are the ________.
rectus abdominis
This lower limb muscle, which attaches the the knee is extended, is the _________.
Gastrocnemius
The ________is the largest and most superficial of the gluteal muscles.
gluteus maximus
True/False
Another name for a muscle cell is muscle fiber?
True
Skeletal muscle is:
epimysium
The functional unit of skeletal muscle is the
sarcomere
The thin filament of muscle cells is called
actin
the thick filaments of muscle are
myosin
True/False
When the thick and thin filaments link together they form what are called crossbridges.
True
Myglobin has a special funtion in muscle tissues. It______________.
holds a reserve supply of oxygen in the muscle
In skeletal muscle which region or organelle contains the highest concentration of calcium ions in a resting muscle fiber?
sarcoplasmic reticulum (SR)
The theory of muscle contaction is called
sliding filament model