MSS_Exam 1

• 1. Epithelial
• 2. Connective
• 3. Muscle
• 4. Nervouse

Epithelial tissue = closely apposed cells with very little intercellular substances between them; arranged in sheets to either cover or line surfaces of the body or to form glands.

Classification by shape and nubmer of cell layers

• Cellularity: composed almost entirely of cells
• Special contact: form continuous sheets held together by tight junctions and desmosomes
• Polarity: apical and basal surfaces
• Supported by c.t.: reticualr and basal laminae
• Avasular but innnervated: no blood vessels but supplied by nerve fibers
• Regenerative: rapidly replaces lost cells by cell division

• 1. Squamous: flat cell, width greater than height
• 2. Cuboidal: cube shape
• 3. Columnar: column shape, height greater tahn width

• 1. Simple squamous: single layer of flat cells with disc-shpaed central nuclei and sparse cytoplasm
• 2. Simple cuboidal: single layer of cubelike cells with large, spherical central nuclei
• 3. Simple columnar: single layer of tall cells with routh to oval nuclei; some cells bear cilia; layer may contain goblet cells (mucus-secreting unicellular glands)

• FUNCTION:
• - passage of material by diffusion and filtration in sites where protection is not important
• - secretes lubricating substances in serosae

• LOCATION:
• - kidney glomeruli
• - air sacs of lungs
• - lining of heart
• - blood vessels
• - lymphatic vessels
• - lining of vetnral body cavity (serosae)

FUNCTION: secretion and absoprtion

• LOCATION:
• - kidney tubule
• - ducts and secretory portion of small glands
• - ovary surfaces

SIMPLE CUBOIDAL

SIMPLE SQUAMOUS ENDOTHELIAL CELLS (line blood vessels)

FUNCTION: absorption and secretion mucus, enzymes, and other substances

• LOCATION:
• Ciliated: help move substances through internal passageways
• - small bronchi
• - uterine tubes
• - some regions of uterus

• Non-ciliated:
• - digestive tract
• - gallbladder
• - excretory ducts of some glands

SIMPLE COLUMNAR EPITHELIAL LAYER

• DESCRIPTION:
• - thick membrane composed of several layers
• - basal cells are cuboidal or columnar and metabolically active
• - surface cells are squamous

FUNCTION: protects underlying tissues in areas subjected to abrasion

• LOCATION:
• Non-keratinized: lines the following
• - esophagus
• - mouth
• - vagina
• Keratinized:
• - skin (dry membrane)

• DESCRIPTION:
• - typically two cell layers thick (both cuboidal)

FUNCTION: secretion and absoption

• LOCATION:
• - sweat glands
• - mammary glands

DESCRIPTION: multiple layer usally with cuboidal at basal layer

FUNCTION: protection and secretion

• LOCATION:
• - pharynx
• - male urethra
• - lining some glandular ducts

DESCRIPTION: single layer of columnar cells (often ciliated) of differing heights; appears stratified and multinucliated; all cells touch basal lamina but not all cells reach apical cell surface

FUNCTION: secretion and propulsion of mucus

• LOCATON:
• - male sperm carrying ducts (non-ciliated)
• - trachea (ciliated)

DESCRIPTION: true stratified layer; basal cells cuboidal or columnar; most apical cell appears to be in "transition"; apical cells may contain double nuclei

FUNCTION: stretching and protection

• LOCATION: lines following:
• - urinary bladder
• - ureter
• - part of urethra

• - Neoplasm: new growth
• - Benign: nonmalignant neoplasm
• - Malignant: uncontrollable growth and dissemination or recurrence after removal
• - Carcinoma: malignant neoplsam derived from epithelial tissue
• - Adenocarcinoma: malignant neoplams of epithelial cells in glandular or gland-like pattern
• - Metastasis: appearance of neoplasms in parts of the body remote from the sites of the primary tumor