USMDO Lecture 1 Overview of Human Physiology

Vocabulary flashcards related to anatomy and physiology lecture notes.

Anterior (ventral)

Front

Posterior (dorsal)

Back

Superior (cranial)

Toward head

Inferior (caudal)

Toward tail

Proximal

Closer to point of origin

Distal

More distant or further away from point of origin

Medial

Closer to midline

Lateral

Further away from midline

Superficial

Closer to surface

Deep

Further below surface

Frontal Plane

Divides body into anterior and posterior parts

Transverse Plane

Divides body into superior and inferior parts or proximal and distal parts

Sagittal Plane

Divides body into right and left parts

Cavity

Any fluid-filled space in body that protects internal organs and help them move and expand

Cranial Cavity

Inside skull; protects brain; filled with cerebrospinal fluid (CSF)

Vertebral (Spinal) Cavity

In vertebral column; protects spinal cord; filled with CSF

Thoracic Cavity

Above diaphragm; subdivided into pleural cavities, mediastinum, and pericardial cavity

Pleural Cavities

Surround each lung

Mediastinum

Between pleural cavities; contains heart, blood vessels, trachea (windpipe), and esophagus; not covered by serous membrane

Pericardial Cavity

Inside mediastinum; within serous membrane that surrounds heart

Abdominopelvic Cavity

Below diaphragm; contains digestive, lymphatic, reproductive, and urinary organs

Serous membrane

Thin sheet of tissue that covers heart, lungs, and abdominal organs and is comprised of 2 continuous membranes that fold over to form double-layered structure

Serous fluid

Watery lubricant found in space between membrane layers, generated by cells of membrane, decreases friction created by moving organs

Visceral layer

In contact with underlying organ

Parietal layer

Outermost layer attached to neighboring structures

Pleural Membrane

Consist of parietal pleura (in contact with thoracic wall) and inner visceral pleura (covers surface of both lungs); space enclosed is pleural cavity

Peritoneal Membrane

Covers some of abdominal organs (e.g., kidneys lie behind parietal peritoneum and are retroperitoneal); made of parietal peritoneum and visceral peritoneum; space between layers forms peritoneal cavity

Pericardial Membrane

Made of parietal pericardium (separates heart from mediastinum) and visceral pericardium (covers surface of heart); space created by two membranes forms pericardial cavity

Feedback

Comprises control mechanisms in biological systems

Positive feedback

Amplify response, moving system further from its starting point

Negative feedback

Counteract change, bringing system back to its set point

Set point

Regulated variable has target value within normal range

Histology

Study of tissues

Tissue

Made of group of cells that share same or similar structure and function; cells are suspended in extracellular matrix (ECM)

Epithelial Tissue

Layers of cells; no visible extracellular matrix; cover body surfaces and line internal cavities; create glands that produce sweat, saliva, and hormones

Connective Tissue

Bind tissues together; abundant ECM, cells scattered throughout; connect, support, and cushion organs and transport substances

Muscle Tissue

Contract and generate force; little ECM; contain contractile proteins actin and myosin

Nervous Tissue

Generate action potentials; contain neurons and neuroglia

Extracellular matrix

Surrounds cells of in tissue; composed of ground substance and protein fibers; provides tensile and compressive strength; directs cell positioning and holds cells in place; regulates development, mitosis, and cell survival

Ground Substance

Fill up most of ECM; made of extracellular fluid (ECF or interstitial fluid); contain water, electrolytes, nutrients; can be gel, solid, or liquid

Glycosaminoglycans

Include chondroitin sulfate, keratan sulfate, heparin, and hyaluronic acid; negatively charged; well-hydrated and traps water in ECM; resist compression

Proteoglycans

Made of GAGs bound to protein core; many proteoglycan molecules bind to very long GAG such as hyaluronic acid, forming proteoglycan aggregates; provide barrier function; give rigidity to ECM; resist compression; protects underlying tissues from invaders

Cell-Adhesion Molecules

Composed of glycoproteins; ensure adherence of cells to other cells and cells to ECM; keep all structures in place; CAMs attach to surface proteins, protein fibers (e.g., collagen), and proteoglycans

Protein Fibers

Dispersed within ground substance; elongated molecules; provide tensile strength; involved in structural integrity of tissues and organs; made of multiple fibrous proteins

Collagen Fibers

Most abundant animal protein (40% of all proteins in body); fibrous protein that is tough but flexible; made of repeating triplet amino acid subunits; resists tension (pulling and stretching)

Elastic Fibers

Made of protein elastin; distensible allowing tissues to stretch up without breaking; can recoil back to resting length (elastic)

Reticular Fibers

Thin, short Type III collagen fibers; makes meshwork in tissues that supports cells; forms weblike structure of reticuloendothelial organs like spleen or lymph nodes that trap foreign particles and invader cells

Ehlers-Danlos Syndrome

Abnormal collagen fibers; symptoms include recurrent joint dislocations, hyperextensibility of skin, fragile blood vessels, easy bruising and common bleeding

Marfan Syndrome

Abnormal elastic fibers; symptoms include tall stature, long limbs and fingers, skeletal changes, joint dislocations, heart valve and eye problems, dilated aorta, and aortic dissection (rupture)

Epithelial Tissues

Epithelial tissues are made of tightly packed cells joined together by tight junctions and desmosomes; little to no ECM; rapid turnover

Basal lamina

ECM produced by epithelial cells; made of collagen fibers and ground substance; closest to epithelial cells

Reticular lamina

Produced by underlying connective tissue; made of reticular fibers and ground substance; provide strength

Regeneration

Undergoes fast regeneration and allows tissues to heal

Transcellular transport

Molecule enters cell by crossing plasma membrane, diffuses across cytosol, and exits cell on opposite side

Paracellular Transport

Molecule moves in space between cells

Simple Epithelia

Consists of single cell layer

Stratified Epithelia

Consist of more than one cell layer

Columnar Cells

Tall and elongated; slender rectangles

Cuboidal Cells

Short and square shaped

Squamous Cells

Flattened and elongated; thin

Simple Squamous Epithelium

One cell-layer thick; cells exhibit “fried egg” appearance; functions include absorption and diffusion, rapid transport of materials, reduced friction

Mesothelium

Lines body cavities (pleural, pericardial, peritoneal); forms serous membranes; produces serous fluid

Endothelium

Forms inner lining of heart and blood vessels; found in air sacs (alveoli) of lungs, Bowman’s capsule of nephrons, and lining of blood vessels

Stratified Squamous Epithelium

Made of more than one layer of cells; found in protected locations subjected to mechanical stress

Keratinized stratified squamous epithelium

Apical cells are flat and dead; basal cells are squamous or cuboidal; lack nuclei; full of water-proof keratin protein; provides protection from mechanical damage because of its resistance to friction; restricted to skin where it forms epidermis

Nonkeratinized stratified squamous epithelium

Apical cells are flat, alive, and have nuclei; protection from abrasion and invaders; maintenance of moisture; areas subjected to mechanical stress like lining of mouth, throat, esophagus, rectum, anus, and vagina

Simple Cuboidal Epithelium

Consists of single layer of cube-shaped cells with large central nucleus; thin and permeable; facilitates rapid diffusion, secretion of mucus, and absorption of molecules; found in ducts of many glands, sections of renal tubules, thyroid, salivary, and mammary glands

Stratified Cuboidal Epithelium

Consists of two-cell layers; relatively rare; found in lining of some large ducts of sweat glands and excretory ducts of salivary glands; functions in protection, secretion, absorption

Simple Columnar Epithelium

One layer of rectangular-shaped cells with nuclei in basolateral side; can have microvilli or cilia; offer limited protection, absorption, and secretion of mucus and other substances

Pseudostratified Columnar Epithelium

One-cell layer thick; appears multilayered because nuclei are positioned at various heights, but all cells lie on basement membrane; have cilia

Stratified Columnar Epithelium

Two or more layers of cells (top layer with columnar cells and basal layer with cuboidal cells); rare in humans; apical cells are columnar; basal cells are cuboidal; functions in protection, minimal absorption and secretion

Transitional Epithelium

Also known as urothelium; made of multiple layers of cells (stratified); basal cells are cuboidal while apical cells are dome-shaped when tissue is relaxed; apical cells flatten when stretched; only found in urinary system; can be stretched without damage

Gland

Organ created from epithelial tissue that produces and secretes products from secretory cells

Endocrine glands

Release hormones into bloodstream; ductless

Exocrine glands

Produce exocrine secretions (e.g., sweat, tears); has ducts that open onto epithelial surfaces

Unicellular Glands

Goblet cells are unicellular exocrine glands; found in intestinal epithelium and respiratory tract; produce mucin that forms mucus, thick sticky liquid that protects tissues

Serous glands

Watery secretions

Mucous glands

Secrete mucins (component of mucus)

Mixed exocrine glands

Both serous and mucous

Merocrine Secretion

Released through secretory vesicles (exocytosis) into ducts with no loss of cytoplasm

Apocrine Secretion

Released by shedding membrane-bound vesicle; involves loss of apical cytoplasm; gland must regrow and regenerate

Holocrine Secretion

Released by secretory cell rupturing, which kills gland cell; gland cells constantly regenerated through mitotic divisions by stem cells

Carcinogens

Chemicals that mutate DNA; can induce cancer

Carcinoma

Epithelial cancer

Benign Cancer

Has not invaded other tissues; “pre-malignant”

Malignant Cancer

Cells metastasize (spread) when they release enzymes that break down basement membrane, facilitating migration to new locations

Connective Tissue Functions

Interconnecting, surrounding, and binding– hold organs in place and link them together; structural support; transport; storage; protection

Connective Tissue Matrix

Matrix consists of fibrous proteins and ground substance

Resident cells

Permanent cells of connective tissue

Migrant cells

Roam around different parts of body

Fibroblasts

Most abundant resident cells, elongated cell body, produce protein fibers and ground substance (parts of ECM), including hyaluronan (cellular cement)

Melanocytes

Produce and store brown pigment melanin which protects from UV light; originate from neural crest

Adipocytes (fat cells)

Cytoplasm is filled with large lipid droplet

Mast cells

Large resident immune cells containing inflammatory mediators such as heparin and histamine; responsible for inflammation after injury or infection

Phagocytes

Migrant immune system cells that engulf foreign particles and invaders, include macrophages, eosinophils, and neutrophils

Mesenchymal cells

Connective tissue stem cells that are activated in response to injury or infection; give rise to fibroblasts, macrophages, etc.

Collagen Fibers

Long, straight, and unbranched protein; provides strength and flexibility; resists forces in only one direction

Reticular Fibers

Create networks of interwoven fibers (stroma) of various reticuloendothelial system organs (e.g., spleen, lymph nodes, liver); provides strength and flexibility; resists forces in multiple directions; give cells stability and anchorage

Elastic Fibers

Made of protein elastin; branched and wavy; can recoil back to original length if stretched; found in places where elasticity if required

Mesenchyme

First connective tissue in embryos; undifferentiated connective tissue made of stem cells