CHP5 Histology

Stream hormones several organs are both endoexo liver

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: somosomes (cont)- each cell contributes ½ of each desmosome desmosome • Hemidesmosomes= ½ desm. that anchor epi to basement desm. membrane membrane Gap- a ringlike ‘channel’ made of 6 transmembrane proteins ringlike surrounding a H2O-filled channel surrounding • Ions, glucose, amino acids, small solutes pass directly from Ions, cytoplasm to cyto of adjacent cells cytoplasm • Intercalated discs (rapid contraction); in some smooth muscle • Absent in skeletal muscle • Embryos use gap junctions until circulatory system formed Glands Glands Glands- exocrine & endocrine glands; a cell or organ that exocrine secretes substances for use by body or to be eliminated secretes • Composed mostly of epithelial tissue Exocrine= ‘‘secretes into a duct; maintain contact w/ surface secretes by a duct (epi tube that moves secretion to surface) by • Sweat, mammary, tear glands; or released into an organ cavity Sweat, like mouth, intestines like Endocrine= ‘‘ductless’; no surface contact, secrete chemical ductless’; messages, hormones, into blood stream hormones, Several organs are both endo/exo: liver, pancreas, testis, Several ovary, kidney ovary, Viscera have some cells that secrete hormones but not Viscera thought of as glands (brain, heart) thought Exocrine structure Exocrine Exocrine structure- enclosed in fibrous capsule, often w/ enclosed capsule often septa (extensions) that divide interior into lobes & septa lobes lobules (microscopic subdivisons) lobules Glandular classification Glandular Exocrine structure- bld vessels, nerves, gland ducts travel Exocrine thru septa thru • Connective tissue framework of glands (stroma) support & support organizes glandular tissue organizes • Parenchyma cells= synthesize & secrete; usually simple synthesize cuboidal or simple columnar epi cuboidal • Simple glands= single, unbranched duct • Compound= branched duct • Tubular –vs- acinar (dilated sac) acinar • can be both…tubuloacinar gland (pancreas) can Types of secretions- serous, mucous, mixed, & cytogenic Types serous mucous mixed cytogenic glands glands • Serous- thin, watery fluids; sweat, milk, tears, digestive juices • Mucous- tongue, roof of mouth secrete the glycoprotein mucin tongue, which absorbs H2O, forming mucus which Classification (cont.) Classification Types of secretions (cont.)~ • Mixed glands- contain both serous & mucous cells; 2 prs of contain salivary glands in chin salivary • Cytogenic glands- release whole cells; testes, ovaries Methods of secretion~ merocrine (eccrine) or holocrine merocrine holocrine glands glands • Merocrine- vesicles that release their secretions by exocytosis • Tear glands, pancreas, gastric glands, etc. • Holocrine- product accumulates & then cell disintegrates product leaving product & cell fragments; often thicker secretions than merocrine • Oil-producing glands in scalp • Apocrine- axillary & mammary glands w/ merocrine-like axillary secretion but different function & histology secretion Membranes Membranes Cutaneous mem- skin…largest membrane; stratified skin…largest sqamous epi (epidermis) resting on layer of c.t. (dermis) sqamous • Relatively dry, retards dehydration, provides unfavorable env Relatively for growth of infectious agents for 2 internal membranes: mucous & serous • Mucous- llines passageways opening to external env; 2-3 ines layers layers • Epithelium, areolar c.t. (lamina propria), layer of smooth muscle Epithelium, (muscularis mucosae) (muscularis • Absorptive, secretory, protective functions • Mucus secreted by goblet cells, multicellular mucous glands • Ciliated in some • Serous- simple sqamous epi resting on thin layer of areolar simple c.t.; produce watery serous fluid that arises from blood (thus similar to blood serum) similar • Line insides of some body cavities, smooth outer surface on Line viscera, pleurae, pericardium, peritoneum Membranes Membranes Endothelium- simple sqamous epi lining circulatory system; simple • Rests on thin layer of areolar c.t. which then rests on elastic Rests sheet; forms tunica interna of blood vessels; endocardium of tunica endocardium heart heart Mesothelium- another name for serous mem lining pleural, another pericardial, & peritoneal cavities pericardial, Synovial membranes- fibrous mem (c.t. only) lining some fibrous skeletal joints skeletal • Secretes synovial fluid into joint Changes in tissue type- differentiation; metaplasia (mature Changes differentiation metaplasia tissue changes to different type) tissue Tissue growth- grow in # (hyperplasia) or increase in size or (hypertrophy) Tissue shrinkage & death Tissue Neoplasia- development of a tumor (neoplasm)…abnormal development nonfunctional tissue nonfunctional Atrophy- decrease in tissue size due to loss in cell size or #s • Results from aging (senile atrophy) or lack of use (disuse Results atrophy) atrophy) Necrosis- premature tissue death due to trauma, toxins, premature infection, etc. infection, • Gangrene= necrotic tissue resulting from insufficient blood necrotic supply Infarction- sudden death of tissue Infarction sudden • Myocardial infarction= dead cardiac tissue • Decubitus ulcer= bed sore Apoptosis (programmed cell death)- normal death of cells • Shrink, die, phagocytized by macrophages Tissue Repair & Insight 5.4 Tissue 2 ways to repair- regeneration or fibrosis • Regeneration= replacement w/ same cell type, restores normal function • Fibrosis= replaced w/ scar tissue made of collagen (produced by fibroblasts); holds organ together but doesn’t restore function Figure 5.33 healing stagesInsight 5.4• Read clinical application: Stem cell controversy...
View Full Document

This note was uploaded on 01/12/2014 for the course ZOO 250 taught by Professor Staff during the Fall '08 term at S.E. Louisiana.

Ask a homework question - tutors are online