Skeletal Muscles Overview

Questions and Answers

About how many skeletal muscles are there in the human body?

over 700

What are the four basic properties of muscle tissue?

Excitability (correct)

Contractibility (correct)

Elasticity (correct)

Extensibility (correct)

What does muscle excitability refer to?

The ability to respond to stimuli

What does muscle contractibility enable?

The ability to shorten and exert a pull or tension Signup and view all the answers

What is muscle extensibility?

The ability to continue to contract over a range of resting lengths Signup and view all the answers

What is muscle elasticity?

The ability to rebound toward its original length Signup and view all the answers

Muscles can push.

False Signup and view all the answers

What are the five jobs of skeletal muscles?

Produce skeletal movements Signup and view all the answers

What causes skeletal movements?

Tendons pulling to move bones Signup and view all the answers

What do stabilized joints do?

Help maintain posture and body position Signup and view all the answers

What soft tissue do skeletal muscles support?

Weight and viscera Signup and view all the answers

What entrances and exits do skeletal muscles regulate?

Swallowing, defecation, and urination Signup and view all the answers

How do skeletal muscles maintain body temperature?

They convert some muscle contraction energy into body heat Signup and view all the answers

What are the five gross anatomical tissues of skeletal muscle?

Blood Vessels Signup and view all the answers

What are the three layers of connective tissue in skeletal muscle?

Perimysium Signup and view all the answers

What is the epimysium?

Dense layer of collagen fibers that surrounds skeletal muscle Signup and view all the answers

What does the epimysium contain?

Blood vessels, nerves, muscle fascicles and muscle fibers Signup and view all the answers

What is the function of nerves in muscle tissue?

Stimulates muscle cell contraction Signup and view all the answers

What is the function of blood vessels in muscle tissue?

Provide oxygen and nutrients needed to produce energy/ATP Signup and view all the answers

What is a neuromuscular junction?

The synapse of the muscle tissue Signup and view all the answers

What happens at the neuromuscular junction?

Neurotransmitter ACh diffuses across the cleft and binds to receptors Signup and view all the answers

What is the perimysium?

Connective tissue partition dividing the whole muscle into fascicles Signup and view all the answers

What does the perimysium contain?

Muscle fascicles and endomysium Signup and view all the answers

What are muscle fascicles?

Bundles of muscle fibers (cells) Signup and view all the answers

Study Notes

Skeletal Muscles Overview

There are over 700 separate skeletal muscles in the human body.

Four Basic Properties of Muscle Tissue

Excitability: Ability to respond to stimuli.
Contractibility: Ability to shorten and exert pull or tension.
Extensibility: Ability to continue contracting over various resting lengths.
Elasticity: Ability to rebound to original length.

Muscle Functionality

Muscles do not push; they pull through contraction involving myosin globular heads pulling on actin filaments.
Skeletal muscles perform five primary jobs:
- Produce movements
- Maintain posture and body position
- Support soft tissues
- Regulate the entrance and exit of materials (e.g., swallowing, defecation)
- Maintain body temperature through conversion of contraction energy into heat.

Skeletal Movement Mechanism

Tendons pull bones to facilitate skeletal movements.
Stabilized joints help maintain posture and body positioning.
Skeletal muscles support body weight and internal organs (viscera).

Connective Tissue in Skeletal Muscle

Composed of five gross anatomical tissues:
- Connective tissue
- Tendons and aponeurosis
- Nerves and blood vessels
Has three layers of connective tissue:
- Epimysium: Dense collagen layer surrounding muscle, contains blood vessels, nerves, fascicles, and fibers.
- Perimysium: Connective tissue partition dividing muscle into fascicles, contains muscle fascicles and endomysium.
- Endomysium: Surrounds individual muscle fibers, containing sarcolemma, nuclei, sarcoplasmic reticulum, myofibrils, and filaments.

Nerve and Blood Vessel Functions

Nerves penetrate muscle tissue, stimulating contraction through chemical communication at neuromuscular junctions.
Blood vessels run parallel to nerves, branching to form capillary networks that accommodate muscle flexion/extension and deliver oxygen and nutrients for energy production.

Neuromuscular Junction Anatomy

The synapse between a motor neuron and muscle fiber is known as the neuromuscular junction, characterized by:
- An axon terminal that branches to multiple muscle fibers.
- A synaptic cleft where acetylcholine (ACh) diffuses and binds to muscle fiber receptors.

Structure of Muscle Fascicles

Muscle fascicles are bundles of muscle fibers, arranged from large to small:
- Whole muscle > Muscle fascicles > Muscle fibers (cells) > Myofibrils > Myofilaments (Actin/Myosin) > Sarcomeres.

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Description

Explore the fascinating structure and functionality of skeletal muscles. This quiz covers their properties, primary functions, and mechanisms of movement. Test your knowledge on how skeletal muscles contribute to various bodily processes!