Muscle tissue
Below are answers to all 26 review questions based on your notes and standard human anatomy.
What are the three types of muscle tissue?
Skeletal muscle – voluntary; attached to bones; produces movement, posture, and heat.
Cardiac muscle – involuntary; found only in the heart; pumps blood.
Smooth muscle – involuntary; found in the walls of hollow organs and blood vessels; moves substances through the body.
Describe the cardiac muscle.
Cardiac muscle is found only in the wall of the heart (myocardium). It contracts involuntarily and continuously to pump blood throughout the body.Describe the smooth muscle.
Smooth muscle is found in the walls of hollow organs such as the stomach, intestines, bladder, uterus, blood vessels, and respiratory tract. It works involuntarily to move substances through the body.Describe the skeletal muscle.
Skeletal muscle is mostly attached to bones by tendons (and sometimes to skin, such as facial muscles). It is under voluntary control and is responsible for body movement, posture, joint stabilization, and heat production.Describe the perimysium.
The perimysium is a layer of connective tissue that surrounds a bundle of muscle fibers called a fascicle.Describe fascicles.
Fascicles are bundles of muscle fibers wrapped together by the perimysium.Describe the endomysium.
The endomysium is a thin layer of connective tissue that surrounds each individual muscle fiber.Define sarcomeres.
Sarcomeres are the basic functional units of muscle contraction. They contain actin and myosin filaments that slide past one another to shorten the muscle.Define a synergist muscle.
A synergist muscle assists the prime mover (agonist) by helping perform a movement and reducing unnecessary motion.Describe an agonist muscle.
An agonist (prime mover) is the muscle primarily responsible for producing a specific movement.Which two muscles raise the corners of the mouth when contracted?
Zygomaticus major
Zygomaticus minor
What muscle is used for chewing food (mastication)?
The masseter is the primary muscle used for chewing.How many internal intercostal muscles are there?
There are 11 pairs of internal intercostal muscles.Describe the diaphragm.
The diaphragm is a dome-shaped muscle beneath the lungs. It is the primary muscle of breathing. When it contracts, it flattens and increases the size of the chest cavity, allowing air to enter the lungs.Describe the deltoid muscle.
The deltoid covers the shoulder and is responsible mainly for abduction of the arm. It also assists with flexion, extension, and rotation.Describe the biceps brachii.
The biceps brachii is located on the front of the upper arm. Its main actions are flexing the elbow and supinating the forearm.Describe insertion.
Insertion is the attachment point of a muscle that moves during contraction. It is usually farther from the body's midline than the origin.Define antagonist.
An antagonist is a muscle that opposes or reverses the action of the agonist.Difference between orbicularis oculi and orbicularis oris.
Orbicularis oculi: Closes the eyelids (blinking and squinting).
Orbicularis oris: Closes and puckers the lips (kissing and whistling).
What muscle retracts the mandible?
The temporalis muscle retracts the mandible (pulls the jaw backward).Define intrinsic muscles.
Intrinsic muscles have both their origin and insertion within the same body region and produce fine movements.Define extrinsic muscles.
Extrinsic muscles originate outside a body region but insert within it, producing larger movements.Describe the pectoralis major.
The pectoralis major is a large chest muscle that flexes, adducts, and medially rotates the arm. It is important in pushing and lifting movements.Describe the latissimus dorsi.
The latissimus dorsi is a broad back muscle that extends, adducts, and medially rotates the arm. It is important in pulling, climbing, and swimming.Medical terminology:
Paralysis: Loss of muscle function.
Dys-: Bad, difficult, or painful.
Ataxia: Loss of coordination of voluntary muscle movements.
Myotomy: Surgical cutting or incision into a muscle.
Movements of a limb—Define abduction and adduction.
Abduction: Movement away from the body's midline.
Adduction: Movement toward the body's midline.
Q: What are the three types of muscle tissue?
A: Skeletal, cardiac, and smooth.
Q: Which muscle type is voluntary?
A: Skeletal muscle.
Q: Which muscle types are involuntary?
A: Cardiac and smooth muscle.
Q: Where is skeletal muscle found?
A: Attached to bones (and some facial muscles attach to skin).
Q: Where is cardiac muscle found?
A: In the myocardium (wall of the heart).
Q: Where is smooth muscle found?
A: Walls of hollow organs and blood vessels.
Q: What does the acronym MPSH stand for?
A: Movement, Posture, Stabilization of joints, Heat production.
Q: Which muscle type allows you to raise your hand?
A: Skeletal muscle.
Q: What is the organization of skeletal muscle from largest to smallest?
A: Whole muscle → Fascicle → Muscle fiber → Myofibril → Sarcomere → Actin & Myosin.
Q: What is a fascicle?
A: A bundle of muscle fibers.
Q: What is the perimysium?
A: Connective tissue surrounding a fascicle.
Q: What is the endomysium?
A: Connective tissue surrounding one muscle fiber.
Q: What is a sarcomere?
A: The functional unit of muscle contraction.
Q: What are the four steps of muscle contraction?
A: Brain sends nerve signal → Acetylcholine released → Calcium released → Actin and myosin slide.
Q: What does calcium do during contraction?
A: Allows actin and myosin to connect.
Q: What provides the energy for muscle contraction?
A: ATP.
Q: What is an agonist?
A: The prime mover responsible for a movement.
Q: What is an antagonist?
A: A muscle that opposes the action of the agonist.
Q: What is a synergist?
A: A muscle that assists the agonist.
Q: What is the insertion of a muscle?
A: The attachment that moves during contraction.
Q: Which muscles raise the corners of the mouth?
A: Zygomaticus major and zygomaticus minor.
Q: What does the orbicularis oculi do?
A: Closes the eyelids.
Q: What does the orbicularis oris do?
A: Closes and puckers the lips.
Q: Primary muscle used for chewing?
A: Masseter.
Q: Which muscle retracts the mandible?
A: Temporalis.
Q: What does the deltoid do?
A: Abducts the arm.
Q: What does the biceps brachii do?
A: Flexes the elbow and supinates the forearm.
Q: What does the triceps do?
A: Extends the elbow.
Q: What does the quadriceps do?
A: Extends the knee.
Q: What do the hamstrings do?
A: Flex the knee.
Q: What does the pectoralis major do?
A: Flexes, adducts, and medially rotates the arm.
Q: What does the latissimus dorsi do?
A: Extends, adducts, and medially rotates the arm.
Q: What is the diaphragm?
A: The primary muscle of respiration.
Q: How many pairs of internal intercostal muscles are there?
A: 11 pairs.
Q: What is flexion?
A: Decreases the angle of a joint.
Q: What is extension?
A: Increases the angle of a joint.
Q: What is abduction?
A: Movement away from the midline.
Q: What is adduction?
A: Movement toward the midline.
Q: What is pronation?
A: Turning the palm downward.
Q: What is supination?
A: Turning the palm upward.
Q: What is dorsiflexion?
A: Toes move upward.
Q: What is plantar flexion?
A: Toes point downward.
Q: What are intrinsic muscles?
A: Muscles whose origin and insertion are within the same body region.
Q: What are extrinsic muscles?
A: Muscles that originate outside a region but insert within it.
Q: What does paralysis mean?
A: Loss of muscle function.
Q: What does dys- mean?
A: Bad, difficult, or painful.
Q: What is ataxia?
A: Loss of coordination of voluntary movements.
Q: What is a myotomy?
A: Surgical incision into a muscle.