Flashcards in Tissues Deck (35)
Epithelial tissues in general
Epithelial cell layer on surface (avascular)
Basal lamina (ECM) and a reticular lamina compose the basement membrane.
Little ECM and often junctional specialization (tight junctions, desmosomes and gap junctions)
Frequent cell division because of exposure to exterior/lumen (called free surface)
Thin = adapted for diffusion (gas, blood, waste, nutrients), filtration (urine in kidney glomeruli) and secretion (lubricating of lining body cavities)
Alveoli lungs, kidney glomeruli (bowman's capsule), lining heart, blood/lymphatic vessels.
Secretion and absorption
Kidney tubules, small glands, ovary
Ciliated= secretion/moving of mucus.
Small bronchi, uterine tubes, uterus.
Non-ciliated= contain microvilli = high absorption. Absorption and secretion in GI tract
Ciliated= Secretion and propulsion of mucus
Trachea, bronchi, respiratory tract.
Non-ciliated= Lining of male urethra
Thickest of all epithelia = protection
Keratinized= retains water, protects against friction and bacteria. Skin epidermis
Non-keratinized= Lining of wet surfaces like epiglottis, vestibule of mouth, tongue, esophagus, vagina
Largest ducts of sweat glands, mammary glands, salivary glands and urethra.
Protection and secretion
Very rare! Lines urethra, Large ducts of some glands and portion of conjunctiva of the eye
Lining of organs that stretch like bladder, ureters and urethra. Urinary organs
Stratified epithelium will be called accordingly
To the layer closest to free surface (lumen)
Endocrine: No free surface, secrete Hormones into Blood, most of endocrine glands are epithelial derivatives formed by invagination and during embryo development they lose their ducts.
Exocrine: Release products onto free surface (skin or lumen) like GI, respiratory or reproductive tract.
1. Merocrine: no part of cell is lost (salivary)
2. Apocrine: top of cell is lost with secretion (mammary)
3. Holocrine: whole cell detaches with secretion (sebaceous)
Endocrine Master gland: Control center, controls anterior pituitary gland hormones
TSH: thyroid stimulating hormone: stimulate thyroid to produce Thyroxine (T4) and triiodothyronine (T3): brain development, metabolism, reproduction.
ACTH: adrenocorticotropic hormone: stimulates cortisol secretion from adrenal cortex
GH: growth hormone
FSH: follicle stimulating hormone and LH luteinizing hormone: act on gonads, growth of follicle, ovulation, stimulation of testosterone, fsh in male, androgen binding protein expression BREF sexual cell stimulation!
PRL: prolactin: milk synthesis from mammary glands
MSH: melanocyte stimulating hormone
ADH/vasopressine: acts on kidney, water retention
Oxytocin- milk let down and uterine contraction during delivery
Smaller endocrine glands (other glands)
Pineal gland: produces melatonin, sleep
Thyroid gland: produces T3,T4, calcitonin. To decrease plasma, controls energy metabolism.
Adrenal cortex: mineralocorticoid like aldosterone (water retention), corticosteroids (increases bp and blood sugar and reduces immune responses, case of stress) and androgens for sex steroids
Adrenal medulla epinephrine and norepinephrine: stress adaptation
Pancreas: insulin, glucagon, somatostatin: nutrient utilization
Gonads: produces testosterone estrogen and progesterone.
General functions of connective tissues.
1. Support, binding. ex: Bone, cartilage, ligaments, tendons, connective tissue around other types of tissues.
2. Protection, defense, repair. Ex: Scar tissue, skull.
3. Insulation: fat cells (adipocytes).
4. Transportation. Blood cells.
ECM is made of
Ground substance: mineralized (bone), gelatinous(loose,dense, cartilage, adipose), watery (blood). Made of proteoglycans (polysaccharide groups on proteins allow to trap more or less water) and cell adhesion proteins (attach cells to ECM)
Protein fibers: fibronectin reticular (connect cells to ECM and support organs), fibrilin reticular (forms filaments and sheets to support organs), elastin (strech, yellow), collagen (stif but flexible, shiny white)
cells that secrete ECM in connective tissue proper
cells that secrete ECM in cartilage. 3 types of cartilage: hyaline (most common,looks like shiny eyes looking at us oo), elastic(elastic fibers), fibrocartilage(collagen fibers). Hyaline cartilage is repaired by fibrocartilage scar tissues.
cells that secrete ECM in bone
cells that secrete ECM in blood
Cells: RBCs (no nucleus), monocyte(neutrophils, moonshaped shadow), lymphocytes (type of WBCs, smaller), eosinophils (2 nuclei)
Loose connective tissue
ECM: more ground substance than fibers (collagen, elastic, reticular)
Skin, around blood vessels, organs, under eptithelia
Dense irregular connective tissue
ECM: more fibers (random collagen) than ground substance
Muscle, nerve sheats
Dense regular connective tissue
ECM: more fibers (parallel collagen) than ground substance
Cells: adipocytes (brown and white)
ECM: little ground substance and no fiber
ECM: ground substance is hyaluronic acid (firm/flexible) and fibers are collagen
Cells: osteoblasts and osteocytes
ECM: ground substance is mineralized (calcium salts) and fibers are collagen
In general, ECM is made of
proteoglycans, fibrous proteins, glycosoaminoglycans