Anatomy & Physiology Exam 1 Study Guide: Cells, Tissues, and Integumentary System

Cell Structure and Function

Introduction to Cells

Cells are the basic structural and functional units of all living organisms. Understanding their structure and function is fundamental to anatomy and physiology.

• Plasma Membrane: The outer boundary of the cell, composed primarily of a phospholipid bilayer with embedded proteins. It regulates the movement of substances in and out of the cell.

• Cytosol: The main component of the cytoplasm, consisting of a gel-like substance where organelles are suspended.

• Organelles: Specialized structures within the cell that perform distinct functions (e.g., mitochondria, lysosomes, endoplasmic reticulum).

Genetic Material and Cell Division

Genetic material in the form of DNA is essential for cell function, replication, and inheritance. Cell division is a tightly regulated process that ensures genetic continuity.

• DNA: Deoxyribonucleic acid, the molecule that contains genetic instructions for the development and function of living things.

• RNA: Ribonucleic acid, involved in protein synthesis and gene regulation. mRNA (messenger RNA) carries genetic information from DNA to ribosomes.

• Difference between RNA and DNA: DNA is double-stranded and contains deoxyribose sugar; RNA is single-stranded and contains ribose sugar.

• Mitosis: The process of cell division that results in two genetically identical daughter cells. The phases are Prophase, Metaphase, Anaphase, Telophase (PMAT).

• Effect of colchicine on cell division: Colchicine inhibits microtubule polymerization, preventing chromosome separation during mitosis.

Cellular Organelles and Functions

• Lysosomes: Organelles containing digestive enzymes; dysfunction can cause cellular swelling and diseases (e.g., Tay-Sachs disease).

• Endoplasmic Reticulum (ER): Network of membranes involved in protein and lipid synthesis. Rough ER has ribosomes; Smooth ER does not.

• Ribosomes: Sites of protein synthesis.

• Microtubules: Cytoskeletal components important for cell shape, transport, and division.

Tissues and Histology

Types of Tissues

Tissues are groups of similar cells that perform a common function. The four basic types are epithelial, connective, muscle, and nervous tissue.

• Epithelial Tissue: Covers body surfaces and lines cavities. Example: Simple squamous epithelium lines air sacs in the lungs.

• Connective Tissue: Supports, binds, and protects organs. Includes bone, blood, adipose, and cartilage. Blood is considered a connective tissue.

• Specific Connective Tissues: Dense regular connective tissue, dense irregular connective tissue, and cartilage (e.g., fibrocytes are cells found in connective tissue).

Cell Junctions and Glands

• Cell Junctions: Structures that connect cells together. Different types include tight junctions, desmosomes, and gap junctions.

• Glands: Epithelial structures that secrete substances. Exocrine glands have ducts; endocrine glands secrete hormones directly into the bloodstream.

Integumentary System

Skin Structure and Function

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

• Epidermis: The outermost layer of skin, composed of stratified squamous epithelium. Contains several layers, including the stratum corneum (outermost) and stratum basale (deepest).

• Dermis: The layer beneath the epidermis, containing connective tissue, blood vessels, nerves, and glands. The dermis has two major layers; the reticular layer is the thickest.

• Melanocytes: Cells in the stratum basale that produce melanin, the pigment responsible for skin color.

• Skin Color: Changes in skin color can indicate disease or homeostatic imbalance. For example, jaundice (yellowing) may indicate liver dysfunction.

Glands of the Skin

• Sudoriferous (Sweat) Glands: Produce sweat for thermoregulation. Two main types: eccrine (found all over the body) and apocrine (found in specific areas like armpits).

• Sebaceous Glands: Secrete sebum (oil) into hair follicles to lubricate skin and hair.

• Burns: Immediate threat is fluid loss; burns are classified by depth (first, second, third degree).

Skin Cancer

• Types of Skin Cancer: Basal cell carcinoma, squamous cell carcinoma, and melanoma. Know how to distinguish between them based on origin and appearance.

Hair Structure

• Hair: Composed of keratinized cells. Be able to define and describe the structure and function of hair.

Summary Table: Major Skin Glands

Gland Type	Secretion	Location	Function
Eccrine Sweat Glands	Watery sweat	All over body	Thermoregulation
Apocrine Sweat Glands	Thicker, milky secretion	Armpits, groin	Activated at puberty, scent
Sebaceous Glands	Sebum (oil)	Associated with hair follicles	Lubricates skin and hair

Key Terms and Definitions

• Plasma Membrane: The cell's outer boundary, composed of a phospholipid bilayer.

• Microtubules: Cytoskeletal structures important for cell division and transport.

• Fibrocyte: A cell found in connective tissue that maintains the extracellular matrix.

• Melanocyte: A cell that produces melanin pigment in the skin.

• Stratum Corneum: The outermost layer of the epidermis, consisting of dead keratinized cells.

• Stratum Basale: The deepest layer of the epidermis, where cell division occurs.

Additional info:

• Colchicine is used experimentally to study mitosis by arresting cells in metaphase.

• PMAT is a mnemonic for the phases of mitosis: Prophase, Metaphase, Anaphase, Telophase.

• Skin color is determined by the amount and type of melanin, as well as other pigments and blood flow.