Muscles and Skin Overview

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Questions and Answers

What is the primary function of the skin in regulating body temperature?

Sweat production and blood flow regulation (correct)

Producing keratin

Creating a barrier against pathogens

Providing vitamin D synthesis

Which type of epithelium primarily composes the epidermis?

Cuboidal epithelium

Pseudostratified columnar epithelium

Keratinized stratified squamous epithelium (correct)

Simple squamous epithelium

What role do melanocytes play in the skin?

Provide melanin for pigmentation (correct)

Act as immune defenders

Produce keratin

Detect touch sensations

Which of the following is NOT a function of the skin?

Production of hormones Signup and view all the answers

What tissue primarily composes the dermis layer of the skin?

Dense irregular connective tissue Signup and view all the answers

What is the main component of the subcutaneous layer, or hypodermis?

Loose connective tissue and adipose tissue Signup and view all the answers

What type of cells in the epidermis are responsible for immune defense?

Langerhans cells Signup and view all the answers

Which skin appendage is responsible for producing sebum?

Sebaceous glands Signup and view all the answers

What is the role of the origin in skeletal muscle?

It is the muscle attachment that moves the least. Signup and view all the answers

Which muscle is primarily responsible for knee extension?

Quadriceps femoris Signup and view all the answers

What is the primary function of the diaphragm?

Separates the thorax from the abdomen. Signup and view all the answers

Which muscle is involved in upper limb abduction?

Supraspinatus Signup and view all the answers

What connects muscles to each other or to the parts they move?

Aponeurosis Signup and view all the answers

Which of the following muscles primarily supports the pelvic region?

Pelvic floor muscles Signup and view all the answers

Which part of the thorax contains the heart and major vessels?

Mediastinum Signup and view all the answers

What muscle group is responsible for lateral rotation of the arm?

Infraspinatus and teres minor Signup and view all the answers

What is the primary function of the sebaceous gland?

To produce sebum that moisturizes hair and scalp Signup and view all the answers

Which structure is responsible for causing hair to stand up?

Arrector pili muscle Signup and view all the answers

Which component is not associated with hair follicles?

Sweat gland Signup and view all the answers

What is the role of the agonist muscle during movement?

To contract and produce the specific movement Signup and view all the answers

Which of the following areas lacks hair follicles?

Palms of the hands Signup and view all the answers

What type of muscle is primarily involved in voluntary movements?

Skeletal muscle Signup and view all the answers

Which of the following best describes the function of sweat glands?

To regulate body temperature through sweat secretion Signup and view all the answers

What is the term for muscles that assist the agonist in performing a movement?

Synergists Signup and view all the answers

Which valve is located between the left atrium and the left ventricle?

Mitral (Bicuspid) Valve Signup and view all the answers

What is the function of the pericardium?

To serve as a lubricated container for the heart Signup and view all the answers

What separates the right ventricle from the pulmonary artery?

Pulmonary Valve Signup and view all the answers

Which part of the heart is responsible for the rhythmic contraction process?

Conducting System Signup and view all the answers

Which of the following arteries supply blood to the heart?

Left coronary artery Signup and view all the answers

How many lobar bronchi correspond to the right main bronchus?

Three Signup and view all the answers

What structure allows time for the atria to empty their blood into the ventricles before they contract?

Atrioventricular node Signup and view all the answers

Which of the following veins is not part of the major blood vessels of the heart?

Femoral vein Signup and view all the answers

What is the arrangement of intercostal nerves and blood vessels from top to bottom?

intercostal vein, intercostal artery, intercostal nerve Signup and view all the answers

Which muscle fibers run inferomedially in the intercostal spaces?

External intercostal Signup and view all the answers

What is the primary function of pleural fluid?

To reduce friction during respiration Signup and view all the answers

Which layer of pleura directly covers the lungs?

Visceral pleura Signup and view all the answers

What anatomical structure separates the right atrium from the right ventricle?

Tricuspid valve Signup and view all the answers

What is the primary role of the cardiovascular system?

To pump blood to tissues and transport gases Signup and view all the answers

How is the pleura categorized?

Visceral and parietal Signup and view all the answers

What shape does the heart primarily have?

Pyramidal Signup and view all the answers

Study Notes

Muscles and Skin

Skin is the largest organ by weight and surface area.
Skin thickness varies; thinnest in eyelids, thickest in heels.
Skin functions include:
- Protection: Barrier against pathogens, chemicals, radiation, and physical injury.
- Regulation: Regulates body temperature via sweat production and blood flow.
- Sensation: Contains nerve endings sensitive to touch, pain, temperature, and pressure.
- Metabolism: Involved in vitamin D synthesis when exposed to sunlight.
- Immune Defense: Plays role in the body's immune response.

Structure of the Skin

Two major layers:
- Epidermis: Outer, thinner layer; composed of epithelial tissue, avascular.
- Dermis: Inner, thicker vascular layer.

Epidermis

Outermost layer; composed of keratinized stratified squamous epithelium.
Provides protective barrier.
Contains cells like:
- Keratinocytes: Most abundant; filled with keratin, acting as a barrier.
- Melanocytes: Produce melanin (skin pigment).
- Langerhans cells: Involved in immune defense against pathogens.
- Tactile epithelial cells (Merkel cells): Fewer in number; responsible for touch sensation.

Dermis

Deeper skin layer.
Composed of dense irregular connective tissue with collagen and elastic fibers.
Provides tensile strength and elasticity.
Contains fibroblasts, macrophages, nerve cells, and adipocytes.
Houses blood vessels, nerves, glands, and hair follicles.

Subcutaneous Layer (Hypodermis)

Located beneath the dermis; not part of the skin.
Composed of loose connective tissue and adipose (fat) tissue.
Contains collagen and elastin fibers; blood vessels and nerves.
Attaches skin to underlying tissue/organs.
Plays roles in heat insulation, energy storage, anchoring, and cushioning the underlying structures.

Appendages of the Skin

Nails: Keratinized plates on dorsal surfaces of fingers and toes.
Hair follicles: Invaginations of epidermis into dermis; where hair grows.
- Hair shaft: Visible part.
- Hair follicle: Structure beneath the skin producing hair.
  - Sebaceous glands: Associated with hair follicle; produce sebum (oils hair and scalp).
  - Arrector pili muscles: Small muscles attached to hair follicles; cause goosebumps.
  - Hair bulb: Base of hair follicle; where hair growth begins.
Sweat glands: Tubular glands distributed over most of the body; produce sweat for temperature regulation & pathogen defense.

The Nails

Keratinized plates on the dorsal surfaces of fingers and toes.
Proximal edge is the root of the nail.
Nail folds surround the nail.
Nail bed is the surface of skin the nail covers.

Hair and Hair Follicles

Distributed over the body (except lips, palms, and soles).
Follicles are invaginations of epidermis into dermis; hair grows out from them.

Sebaceous Glands

Located beneath the epidermis, near hair follicles.
Secrete sebum (oil) onto hair shafts.
Helps maintain hair flexibility and oils the skin around the follicle opening.

Sweat Glands

Long, tubular glands distributed over most of the body (except red margins).
Secrete sweat to regulate body temperature and offer some pathogen defense.

Types of Muscles

Skeletal muscle:
- Striated, voluntary, multi-nucleated fibers.
- Attached to skeleton.
Smooth muscle:
- Non-striated, involuntary, spindle-shaped fibers.
- Usually in the walls of internal organs.
Cardiac muscle:
- Striated, involuntary, branched fibers.
- Only in the heart walls.

Skeletal Muscle Terminology

Muscle: Special connective tissue with contractility.
Agonist: The prime mover producing a specific action.
Antagonist: Muscle opposing the agonist's action.
Synergist: Muscles assisting the agonist, stabilizing the joint, and improving efficiency.
Origin: Muscle attachment moving the least (usually proximal).
Insertion: Muscle attachment moving the most (usually distal).
Belly: Fleshy part of the muscle.
Aponeurosis: Sheet-like fibrous tissue connecting muscles or muscles to other structures, not bones.
Tendons: Connect muscles to bones.

Thorax

Region between neck and abdomen.
Separated from the neck and abdomen by the diaphragm.
Protects lungs and heart.
Provides attachment points for thorax, upper extremity, abdomen, and back muscles.

Thoracic Cavity

Divided into:
- Mediastinum: Contains heart, major blood vessels, thymus, and lymph nodes.
- Two pleural cavities: Each contain a lung.

Thoracic Wall

Formed by:
- Thoracic portion of vertebral column.
- Sternum and costal cartilages.
- Ribs and intercostal spaces.
- Suprapleural membrane.
- Diaphragm.

Chest Wall

Skin, superficial fascia (subcutaneous tissue), and respiratory accessory muscles (e.g., serratus anterior).
- Superficial fascia: Loose connective tissue layer containing blood vessels, fat, and nerves; supports and protects underlying tissue.

Intercostal Spaces

Spaces between ribs containing muscles for respiration:
- External intercostals.
- Internal intercostals.
- Innermost intercostals.
- Intercostal nerves and blood vessels (arranged in VAN order).
Endothoracic fascia: A loose connective tissue layer separating the innermost intercostal muscles from the pleura.

Pleura

Sac composed of two mesothelial layers (visceral and parietal).
Visceral pleura: Covers the lungs following their contours.
Parietal pleura: Lines the inner chest wall, diaphragm, and superior mediastinum.
Pleural cavity: Space between visceral and parietal pleura containing fluid reducing friction during respiration.
Functions: Lubrication, pressure regulation, protection.

Cardiovascular System

Composed of heart, blood vessels, and blood.
Heart acts as a pump pushing blood to organs.
Blood carries oxygen and nutrients to cells.
Blood carries carbon dioxide and waste products back to the heart.

Heart

Muscular organ (250-400 grams).
Pyramidal shape, within the pericardium, behind the sternum.
Composed of four chambers forming two separate pumps.
- Chambers: Right atrium, Right ventricle, Left atrium, Left ventricle
- Valves: Tricuspid, Pulmonary, Mitral (Bicuspid), Aortic

Heart Valves

Control blood flow within the heart:
- Tricuspid: Right atrium to right ventricle.
- Pulmonary: Right ventricle to pulmonary artery.
- Mitral (Bicuspid): Left atrium to left ventricle.
- Aortic: Left ventricle to aorta.

Arterial Supply of the Heart

Supplied by the right and left coronary arteries.
Arise from the ascending aorta.
Coronary arteries and branches distribute over the surface of the heart.

Conducting System of the Heart

Generates rhythmic contractions (70-90 beats/minute).
Impulse originates spontaneously in the conducting system (Sinoatrial node).
Atria contract first; followed by ventricles.
Delay in impulse transmission allows atria to empty before ventricles contract.

Major Blood Vessels

Aorta: Major artery branching off to many branches.
Pulmonary arteries: Carry deoxygenated blood to lungs.
Pulmonary veins: Return oxygenated blood to the heart.
Superior vena cava: Major vein returning blood from upper body.
Inferior vena cava: Major vein returning blood from lower body.

Blood Circulation

Oxygen-rich blood from lungs to body.
Oxygen-poor blood from body to lungs.

Lungs

Two organs in thoracic cavity for gas exchange.
Lobe-segment structure.
Fissures divide different lobes.

Bronchial Tree

Trachea divides at carina into right and left main bronchi.
Bronchi branch into secondary bronchi (lobar) for each lobe.
Further branching into segmental bronchi and bronchioles to alveolar ducts and alveoli for gas exchange

Lung Lobes and Fissures

Lungs are divided into lobes.
Fissures separate lobes.

Blood Supply

Pulmonary arteries: Carry deoxygenated blood to lungs.
Pulmonary veins: Return oxygenated blood to the heart.
Bronchial arteries: Supply oxygenated blood to lung tissue.

Gas Exchange

Occurs in alveoli.
Gas diffuses between air in alveoli and blood in capillaries.
Oxygen enters blood, carbon dioxide leaves.

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Description

This quiz covers the fundamental concepts of muscles and skin, including the structure and functions of skin as the largest organ. You'll explore the layers of skin, from the epidermis to the dermis, and learn about the roles they play in protection, regulation, and sensation.