Human Anatomy and Physiology Vocabulary PDF

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Human Anatomy and Physiology Vocabulary

Chapter 4: The Tissue Level of Organization • Tissues- specialized cells and cell products that carry out a limited number of functions • Histology- study of cells

Epithelial Tissue: Epithelial Tissue- closely spaced cells in layers that cover surfaces and organs, and line internal passageways (cavities and ducts), and form glands • Function: protection, secretion and absorption • Epithelia- layers of cells that cover internal or external surfaces • Glands- structures that produce fluid secretions • Cell Junctions- specialized areas of the plasma membrane that attach a cells to another cell or to extracellular materials • Gap junction- plasma membrane channels form a narrow passageway that lets small molecules and ions pass from cell to cell • Essential for coordinated muscle cell contractions in cardiac and smooth muscle • Tight junction- lipid portions of the two plasma membranes are tightly bound together to prevent water and solutes from passing between cells (digestive tract/stomach acid) by interlocking membrane proteins • Adhesion belt- forms an inferior band that encircles cells and binds them to neighbors • Lumen- passageway that exposes apical surfaces of epithelial cells are exposed to the space inside the tube • Desmosome- dense areas that are very strong and can resist stretching and twisting to the cytoskeleton (skin peels off in sheets) • Spot desmosomes- small discs connected to bands of intermediate filaments; stabilizes the shape of a cell • Hemidesmosomes- anchors the epithelia cells to the basal lamina/ underlying tissues • Germinative cells- stem cells near the basal lamina produce new epithelial cells once the previous ones die

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Human Anatomy and Physiology Vocabulary

• Polarity- presence of structural and functional differences between the exposed and attached surfaces • Apical surface- faces external environment • Basal surface- faces internal environment • Basal Lamina- basement membrane that is the basal surface • Ciliated epithelium- epithelial tissue that contains Cilia, which moves substances over the epithelial surface (moves mucus in respiratory tract)

• Simple epithelium- only one layer of cells cover the basement membrane (lining of intestines and alveoli for gas exchange) • Stratified epithelium- several layers of cells cover the basement membrane (surface of the skin and lining of the mouth) 1. Squamous epithelium- thin, flat, and somewhat irregular in shape A. Simple squamous epithelium- body’s most delicate type of epithelium that protects regions where absorption or diffusion take place, or where a slick, slippery surface reduces friction (alveoli in lungs, lining of thoracic and abdominopelvic body cavities, lining of heart and blood vessels) • Function- reduces friction; controls vessel permeability; performs absorption and secretion (of serous fluid) 1. Mesothelium- simple squamous epithelium line the body cavities that enclose the lungs, heart, and abdominal organs (parietal-outside) 2. Endothelium- simple squamous epithelium lining the inner surface of the heart and all blood vessels (visceral-inside)

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Human Anatomy and Physiology Vocabulary

B. Stratified squamous epithelium- forms a series of epithelial layers that are located where mechanical stresses are severe (surface of skin, lining of mouth, esophagus, and anus); protection from abrasion and barrier to infection • Function- provides physical protection against abrasion, pathogens, and chemical attack 1. Keratinized- apical (surface) cells are dead, lack nuclei, and contain the protein keratin which is tough and water resistant (outer layer of skin) 2. Nonkeratinized- alive cells that lack keratin that resist abrasion but will dry out and die if not kept moist (oral cavity, pharynx, esophagus, anus, vagina)

2. Cuboidal epithelium- resemble hexagonal boxes from their apical surfaces A. Simple cuboidal epithelium- provides limited protection and occurs where secretion or absorption takes place (lines portions of kidney tubules) • Function- limited protection, secretion, absorption B. Stratified cuboidal epithelium- two or more layers of cuboidal epithelium; relatively rare (along ducts of sweat glands, larger ducts of mammary glands) • Function- protection, secretion, absorption

3. Transitional epithelium- tolerates repeated cycles of stretching and recoiling (returning to previous shape) without damage • Urinary bladder (empty- cuboidal epithelium; full- stratified squamous epithelium) • Function- permits expansion and recoil after stretching

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Human Anatomy and Physiology Vocabulary

4. Columnar epithelium- tall and more thin; nuclei are crowded into a narrow band close to basement membrane A. Simple columnar epithelium- absorption and secretion (small intestine, secretions of simple columnar epithelia protect stomach and large intestine against chemical stresses) • Function- protection, secretion, absorption B. Pseudostratified columnar epithelium- columnar epithelium that includes several types of cells with varying shapes and functions (line nasal cavity, trachea, bronchi, male reproductive tract); includes cilia • Function- protection, secretion, move mucus with cilia C. Stratified columnar epithelium- relatively rare that has either two layers or multiple layers (protection along pharynx, epiglottis, anus, urethra, few large excretory ducts) • Function- protection

• Glands- collections of epithelial cells that produce secretions • Endocrine glands- ductless glands release secretions (hormones) into interstitial fluid • Hormones- secretions that enter bloodstream to regulate/coordinate activities of various tissues, organs, and organ systems • Thyroid gland and pituitary glands • Exocrine glands- release secretions into tubular ducts onto an epithelial surface (skin surface or onto an epithelium lining an internal passageway that communicates with the exterior) • Ducts- passageways of glands • Enzymes entering the digestive tract, perspiration on skin, tears in eyes, milk produced by mammary glands

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Human Anatomy and Physiology Vocabulary

• Exocrine Secretion Mode of Secretion: 1. Merocrine secretion- product is released from secretory vesicles by exocytosis • Most Common type of secretion • Mucin- merocrine secretion that mixes with water to form mucus • Mucus- lubricant, protective barrier, and sticky trap for foreign particles and microorganisms • Mucus secretions of salivary glands coat food and reduce friction during swallowing • merocrine sweat glands produce watery perspiration to cool body down 2. Apocrine secretion- involves the loss of cytoplasm as well as secretory product; apical portion of cytoplasm becomes packed with secretory vesicles and then is shed • Milk production in mammary glands involves a combination of merocrine and apocrine secretions 3. Holocrine secretion- destroys the the gland cell; the entire cell becomes packed with secretory vesicles and then bursts, releasing the secretion, but killing the cell • Replacing destroyed gland cells by the division of stem cells • Sebaceous glands, associated with hair follicles, produce an oil hair coating by means of holocrine secretion

• Exocrine Secretion Types of Secretion: 1. Serous glands- secrete watery solution that contains enzymes • Parotid salivary glands 2. Mucous glands- secrete mucins that hydrate to form mucus • Sublingual salivary glands and submucosal glands of small intestine 3. Mixed exocrine glands- can produce either serous or mucous or both • Submandibular salivary glands are mixed exocrine glands

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Human Anatomy and Physiology Vocabulary

• Exocrine Secretion Gland Structure: 1. Unicellular glands- individual secretory cells that have independent, scattered gland cells in epithelia (single-celled) • Goblet cells- mucous cells that secret mucins (digestive tract) 2. Multicellular glands- all other glands that produce exocrine or endocrine secretions • Secretory sheet- gland cells form an epithelium that releases secretion into an inner compartment (mucin- secreting cells protect that organ from its own acids and enzymes by continuously secreting mucin A. Structure: (1) Simple- one duct that doesn’t divide to gland cell (NO branching) (2) Compound- duct divides one or more times to gland cells (branching) B. Shape (secretory portion): (1) Tubular- form tubes; either straight or coiled (2) Alveolar/acinar- form blind pockets (3) Tubuloalveolar/tubuloacinar- form both tubes and pockets

Connective Tissue: Connective Tissue- creates the basement membrane of all epithelial tissues (connects epithelial to rest of body) • Other types (bone, fat, and blood) provide structure, store energy, and transport material throughout body, respectively. • Functions: structural framework, transportation of fluids and materials, protection, supporting and interconnecting other types of tissue, storing energy (triglycerides) defending body

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Human Anatomy and Physiology Vocabulary

• Three basic components that all connective tissues: 1. Specialized cells- from 1 to 8-10 cell types in connective tissue (lymphocytes, chondrocytes, osteocytes, etc) 2. Extracellular protein fibers- 3 types that are produced from fibroblasts 3. Ground substance- Surrounds cells and fibers; semi-viscous (syrupy) fluid containing proteoglycans and glycoproteins found in interstitial space (consistency from watery to jello) • Extracellular Matrix- made up of extracellular protein fibers and ground substance proteins are unpolymerized in fluid connective tissues (blood) • Fibroblasts produce 3 types of extracellular matrix: 1. Collagen fibers- most common; straight and unbranched; formed like a strong rope with protein subunits wound together (tendons and ligaments) 2. Reticular fibers- form a network/web of fibers (stroma) resists forced from all directions. Hold parenchyma cells in position; maintains relative positions • Stroma- network of fibers • Parenchyma- functional cells of an organ 3. Elastic fibers- somewhat rare; made of the protein elastin. Filaments are wavy and stretch. (Ligaments between vertebrae and in large arty walls that allow to recoil after stretch) • Three types of connective Tissue: 1. Connective Tissue Proper A. Loose connective tissues- “packing materials” of body • fill spaces between organs, cushion and stabilize special cells in any organs, and support epithelia; surround and support blood vessels and nerves, store lipids, and provide a route for the diffusion of materials a) Areolar- under epidermis that separates the skin from deeper structures; like adipose with open framework of extracellular proteins and fluid but fewer fat cells

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Human Anatomy and Physiology Vocabulary

b) Adipose Tissue (1) padding around structures (2) insulation under skin (3) Adipocytes- fat cells used for energy storage in specialized cells i)

White fat cell- most adipose tissue

ii) Brown fat- heat production; brown due to many mitochondria and dense vascularity (in infants and young children) c) Reticular- fibrous network forms stroma of liver and pancreas

B. Dense connective tissues- mainly made up of collagen fibers (fibroblasts are few) a) Regular- collagen fibers are parallel, packed tightly, and align with forces applied to tissue; avascular (2D fiber arrangement) (1) Tendons- attach muscles to bones (2) Ligaments- attach bone to bone or stabilize positions of internal organs (3) Elastic tissue- mainly elastic fibers; ligaments that are under transitional epithelium (blood vessels, airways) b) Irregular- No consistent fiber arrangement; strengthens and supports areas subjected to stresses from many directions; found in sheets or as a surrounding layer (3D fiber arrangement) (1) Skin- gives skin its strength (2) Organ capsules- thick fibrous layer that surrounds internal organs and encloses the cavities of joints (3) Jont cavities (4) Periosteum- bones (5) Perichondrium- cartilages 2. Fluid Connective Tissues A. Blood a) Specialized cells- RBCs, leukocytes (WBC) and platelets (formed elements) • Hematocrit- 45% of blood volume Page 8! of !10

Human Anatomy and Physiology Vocabulary

b) Ground substance- plasma proteins dissolved in water (unpolymerized) • What happens when plasma proteins do polymerize? B. Lymph a) Specialized cells- lymphocytes for immune monitoring b) Ground substance- interstitial fluid returning to the vascular system in lymph vessels (very few suspended proteins)

3. Supporting Connective Tissue A. Bone- collagen fibers (1/3rd) and calcium salts (2/3rds of carbonate and phosphate) with very little ground substance fluid a) Mesodermal origin b) Osteocytes- bone cells that live in lacunae inside calcium salt matrix c) Canaliculi- cytoplasmic projections where osteocytes communicate with circulation d) Periosteum- fibrous connective tissue covering (dense irregular) combined with inner cellular layer (functions in appositional growth). e) Unlike cartilage, bone grow and remodels throughout life. Able to heal rapidly unlike cartilage B. Cartilage- gel matrix of chondroitin sulfates (polysaccharides) that form proteoglycans with proteins in ground substance • Chondrocytes- cartilage cells that occupy in lacunae • Lacunae- small chambers • Avascular- slow healing, long diffusion distances • Cartilage growth- only during childhood; only in adults in injury occurs • Interstitial growth- growth from within; chondrocytes divide and produce more matrix • Appositional growth- surface growth; matrix surrounds fibroblasts with differentiate into chondrocytes • Used for injuries in adulthood Page 9! of !10

Human Anatomy and Physiology Vocabulary

• Types: 1. Hyaline cartilage- mostly common type that has clear matrix of collagen fibers • articular (joint) cartilage, nasal, costosternal, respiratory tract cartilage 2. Elastic cartilage- very flexible • Ear, epiglottis, parts of larynx 3. Fibrocartilage- dense collagen matrix that is tough and durable to prevent bone-bone contacts in joints (knee and intervertebral disks)

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