Human Anatomy: The Spine and Muscles

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Questions and Answers

What is the primary function of ligaments in the vertebral column?

To protect the spinal cord from injury

To permit movement in all directions

To hold the vertebral column in an upright position (correct)

To store calcium and phosphate

Which ligament prevents hyperextension of the vertebral column?

Interspinous ligament

Supraspinous ligament

Anterior longitudinal ligament (correct)

Posterior longitudinal ligament

What part of the spine consists of 5 fused bones?

Lumbar

Cervical

Coccygeal

Sacral (correct)

Which of the following conditions is characterized by an abnormal lateral curvature of the spinal column?

Scoliosis Signup and view all the answers

Which bone structure combines to form the cranial cavity?

Cranial bones Signup and view all the answers

What physiological function do bones NOT perform?

Storage of metabolic waste Signup and view all the answers

What can cause an accentuated lumbar curvature, also known as lordosis?

Being overweight or pregnant Signup and view all the answers

How many bones comprise the shoulder girdle?

4 Signup and view all the answers

What are the four important functions of muscle as stated?

Producing movement, maintaining posture, stabilizing joints, generating heat. Signup and view all the answers

Which type of muscle is specialized for rhythmic contractions?

Cardiac muscle Signup and view all the answers

What characterizes skeletal muscle contractions?

Skeletal muscle can contract rapidly but gets tired and needs rest. Signup and view all the answers

What type of connective tissue wraps each muscle fiber?

Endomysium Signup and view all the answers

How does cardiac muscle respond to increased demand?

It accelerates to cope with demand. Signup and view all the answers

Which of the following is NOT a type of muscle tissue?

Nervous tissue Signup and view all the answers

Which statement correctly describes smooth muscle?

Smooth muscle contracts steadily and tirelessly. Signup and view all the answers

What term describes the motor neuron and all the muscle fibers it supplies?

Motor unit Signup and view all the answers

What is a primary role of skeletal muscle in relation to the environment?

Controlling eye movement and facial expressions. Signup and view all the answers

How is the average number of muscle fibers per motor unit characterized?

150, varying from 4 to several hundred Signup and view all the answers

What is the effect of stimulating a single motor unit?

Weak contraction of the entire muscle Signup and view all the answers

Which type of movement involves one flat bone sliding over another?

Gliding Signup and view all the answers

Which type of movement is characterized by the bending motion that decreases the angle between two bones?

Flexion Signup and view all the answers

What type of muscle is characterized by the absence of coarse connective tissue?

Smooth muscle Signup and view all the answers

What does plantar flexion refer to?

Extension of the foot and ankle Signup and view all the answers

What type of muscle organization is primarily found in the walls of hollow organs?

Smooth muscle organized into sheets of closely apposed fibers Signup and view all the answers

Which movement increases the angle between two bones?

Extension Signup and view all the answers

Which type of movement refers to increasing the angle between two bones?

Extension Signup and view all the answers

Which movement involves lifting the foot so that it points toward the shin?

Dorsiflexion Signup and view all the answers

What describes the movement of the radius around the ulna when the palm faces down?

Pronation Signup and view all the answers

What is the action of moving a limb away from the midline of the body called?

Abduction Signup and view all the answers

Which term is used for the movement called 'jutting the jaw out'?

Protraction Signup and view all the answers

What is the term for the movement that involves pulling a body part superiorly?

Elevation Signup and view all the answers

What is the opposite of inversion when referring to the movements of the foot?

Eversion Signup and view all the answers

What occurs during isotonic muscle contraction?

Muscle contracts by becoming shorter and thicker. Signup and view all the answers

Which proteins are part of the actin myofilaments?

Tropomyosin and troponin. Signup and view all the answers

What is the role of acetylcholinesterase in muscle relaxation?

It breaks down acetylcholine to prevent further stimulation. Signup and view all the answers

How is calcium transported during muscle relaxation?

Calcium is actively transported to the sarcoplasmic reticulum. Signup and view all the answers

What structural change occurs to the I Band during relaxation?

The I Band becomes broader. Signup and view all the answers

Which of the following best describes isometric muscle contraction?

Muscle develops tension but remains the same length. Signup and view all the answers

What happens to the binding sites on actin during muscle relaxation?

They are blocked by tropomyosin and troponin. Signup and view all the answers

What is the primary energy source that powers muscle contraction?

Hydrolysis of ATP. Signup and view all the answers

Study Notes

The Spine

The lumbar spine is made up of 5 bones (L1-L5)
The sacrum is made up of 5 fused bones
The coccyx is made up of 4 fused bones
The lumbar spine is responsible for low back movement

Clinical Deviations of the Spine

Scoliosis is an abnormal lateral curvature of the spinal column
Scoliosis typically occurs in an S or C pattern
Lordosis is an accentuated lumbar curvature
Being overweight or pregnant can cause lordosis

Function of Ligaments

Ligaments hold the vertebral column in an upright position
The anterior longitudinal ligament prevents hyperextension and is strong
The posterior longitudinal ligament prevents hyperflexion and is relatively weak

Types of Muscle Contractions

Skeletal muscles can contract rapidly but fatigue easily
Smooth muscles contract slowly and steadily
Cardiac muscle contracts at a steady rate but can accelerate to meet demand

Functions of Muscles

Muscles produce movement
Muscles maintain posture
Muscles stabilize joints
Muscles generate heat

Connective Tissue, Muscle Fibers, and Wrappings

Muscle fibers are the primary components of muscle tissue
Muscles also contain blood vessels, nerve fibers, and connective tissue
Endomysium wraps around each muscle fiber
Muscle fibers are gathered into bundles, wrapped by perimysium
Muscle bundles are wrapped by epimysium

Types of Movements

Gliding: One flat bone slides over another.
Angular: Increases or decreases the angle between two bones.
- Flexion: Bending motion that decreases the angle of the joint.
- Extension: Straightening motion that increases the angle of the joint.
- Hyperextension: Extension beyond a straight position.
Rotation: Movement of a bone around its longitudinal axis.
Special:
- Supination: Palm facing up.
- Pronation: Palm facing down.
- Inversion: Sole of the foot facing inwards.
- Eversion: Sole of the foot facing outwards.
- Protraction: Non-angular motion forwards (e.g., jutting the jaw out).
- Retraction: Non-angular motion backwards (e.g., pulling the jaw back).
- Elevation: Moving a body part upwards.
- Depression: Moving a body part downwards.

Muscle Contractions

Isotonic: Muscle contracts and gets shorter, tension remains constant.
Isometric: Muscle generates tension but doesn't change length.

Muscle Relaxation

Acetylcholinesterase breaks down acetylcholine, preventing further stimulation of muscle fibers.
Calcium ions move away from myofilaments and are actively transported back to the sarcoplasmic reticulum.
Without calcium, troponin and tropomyosin block binding sites on actin, preventing myosin from forming cross-bridges.
Myosin and Actin return to their original positions, causing the I band to widen and the Z lines to move further apart.

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Description

This quiz covers the anatomy and functions of the spine and muscles, focusing on key structures such as the lumbar spine, sacrum, coccyx, and the types of muscle contractions. Additionally, it explores clinical deviations like scoliosis and lordosis, and the role of ligaments in maintaining spinal integrity. Test your knowledge on these essential components of human anatomy!