Anatomy & Physiology Study Guide: Intro, Histology, and Integumentary System

Chapter 1: Intro

Definition of Anatomy and Physiology

Anatomy and physiology are foundational sciences in understanding the structure and function of the human body.

• Anatomy: The study of the structure of body parts and their relationships to one another. It includes both gross anatomy (visible to the naked eye) and microscopic anatomy (requires magnification, e.g., histology and cytology).

• Physiology: The study of the function of body parts and how they work to carry out life-sustaining activities.

• Physiological Variation: Recognize that there is both anatomical and physiological variation between individuals.

Structure-Function Principle

The structure of a body part is closely related to its function. This principle is fundamental in anatomy and physiology.

• Example: The thin walls of alveoli in the lungs facilitate gas exchange.

Levels of Structural Organization

The human body is organized into several levels, from smallest to largest:

• Chemical (atoms, molecules)

• Cellular (cells)

• Tissue (groups of similar cells)

• Organ (two or more tissue types)

• Organ system (organs working together)

• Organism (the whole body)

Definitions of Homeostasis

Homeostasis is the maintenance of a stable internal environment despite changes in external conditions.

• Dynamic equilibrium: Homeostasis involves continuous monitoring and regulation.

• Examples: Regulation of body temperature, blood glucose, and pH.

Types of Homeostatic Regulation

Homeostatic regulation can involve autoregulation, nervous regulation, and hormonal regulation.

• Autoregulation: Local, automatic adjustment by a cell, tissue, or organ.

• Nervous regulation: Rapid, short-term responses via nerve impulses.

• Hormonal regulation: Slower, longer-lasting responses via hormones.

Feedback Mechanisms

Feedback mechanisms maintain homeostasis.

• Negative feedback: The response reduces or shuts off the original stimulus (e.g., regulation of body temperature).

• Positive feedback: The response enhances or exaggerates the original stimulus (e.g., blood clotting, labor contractions).

Directional Terms and Body Planes

Directional terms describe the locations of structures relative to other structures or locations in the body.

• Examples: anterior/posterior, superior/inferior, medial/lateral, proximal/distal.

• Body planes: sagittal, frontal (coronal), transverse (horizontal).

• "Down gradient" vs. "up gradient": Movement from high to low concentration (down) or low to high (up).

Chapter 4: Histology

Primary Tissue Types

The human body is composed of four primary tissue types:

• Epithelial tissue: Covers body surfaces, lines cavities, and forms glands.

• Connective tissue: Supports, protects, and binds other tissues.

• Muscle tissue: Produces movement.

• Nervous tissue: Initiates and transmits electrical impulses.

Epithelial Tissue

• Know the difference between a section, a smear, and a spread.

• Common characteristics: cellularity, polarity, attachment, avascularity, regeneration.

• Cell junctions: Tight junctions (prevent leakage), desmosomes (anchor cells), gap junctions (allow communication).

• Glands: Epithelial tissue forms glands.

• Exocrine glands: Secrete products into ducts (e.g., sweat, salivary glands).

• Endocrine glands: Secrete hormones directly into the bloodstream.

Connective Tissue

• Functions: binding, support, protection, insulation, transportation (blood).

• Common characteristics: cells, fibers (collagen, elastic, reticular), ground substance.

• Loose vs. dense connective tissue: loose has more ground substance, dense has more fibers.

• Membrane types: mucous, serous, synovial; know their locations and functions.

Muscle Tissue

• Functions: movement, posture, heat production.

• Types: skeletal, cardiac, smooth (know characteristics and locations).

Nervous Tissue

• Types of cells: neurons (transmit impulses), supporting cells (glia).

• Functions: communication, control.

Cellular Adaptations and Death

• Hypertrophy: Increase in cell size.

• Hyperplasia: Increase in cell number.

• Metaplasia: Change from one cell type to another.

• Stem cells: Totipotent, pluripotent, multipotent, unipotent (differentiation potential).

• Regeneration: Replacement of destroyed tissue by the same kind of cells.

• Fibrosis: Replacement by scar tissue.

• Atrophy: Decrease in cell size or number.

• Necrosis: Pathological cell death.

• Apoptosis: Programmed cell death.

Chapter 5: The Integumentary System

Organization and Functions

The integumentary system includes the skin, hair, nails, and associated glands. It protects the body, regulates temperature, and provides sensory information.

• Organization: cutaneous membrane (epidermis and dermis), accessory structures, hypodermis (subcutaneous layer).

Epidermis

• Layers: stratum basale, spinosum, granulosum, lucidum (in thick skin), corneum.

• Cells: keratinocytes (produce keratin), melanocytes (produce melanin), dendritic (Langerhans) cells, Merkel cells.

• Keratinization: process by which cells fill with keratin and move to the surface.

• UV protection: melanin absorbs UV radiation; Vitamin D3 synthesis is initiated in the skin.

Dermis

• Composition: collagen and elastic fibers, ground substance, blood vessels, nerves.

• Skin turgor: measure of skin's elasticity.

• Friction ridges: fingerprints; cleavage (tension) lines: orientation of collagen fibers.

• Contusion: bruise; decubitus ulcer: pressure sore.

Skin Color

• Determined by melanin, carotene, and hemoglobin.

• Melanocytes: produce melanin for UV protection.

• Dermal circulation: dilation/constriction of blood vessels affects color (e.g., cyanosis: bluish color due to low oxygen).

• Vitiligo: loss of melanocytes; albinism: lack of melanin production.

Carcinomas vs. Malignant Melanoma

• Carcinomas: cancers of epithelial cells (e.g., basal cell, squamous cell carcinoma).

• Malignant melanoma: cancer of melanocytes, more dangerous due to metastasis.

Subcutaneous Layer (Hypodermis)

• Composition: adipose and areolar tissue.

• Functions: insulation, energy storage, shock absorption.

Hair

• Definition: filamentous strands of dead keratinized cells.

• Function: protection, sensation, insulation.

• Vellus hair: fine, unpigmented; terminal hair: coarse, pigmented.

• Hair grows from the root in the follicle; arrector pili muscle causes hair to stand up.

Nails

• Keratinized structures growing from the nail root; protect fingertips.

Cutaneous Glands

Gland Type	Secretion	Function
Sebaceous	Oil (sebum)	Lubricates skin/hair, antibacterial
Sudoriferous (Sweat)	Sweat	Thermoregulation, excretion
Apocrine	Thicker, milky secretion	Active at puberty, odor
Eccrine	Watery sweat	Cooling, excretion
Ceruminous	Earwax (cerumen)	Protects ear canal
Mammary	Milk	Nutrition for infants

• Know differences between apocrine and eccrine sweat glands.

Injury and Repair

• Four steps of injury repair: inflammation, migration, proliferation, maturation.

Burns

• First degree: affects epidermis only.

• Second degree: affects epidermis and part of dermis.

• Third degree: destroys entire skin layer.

• Rule of nines: method to estimate body surface area affected by burns in adults.