Histology Flashcards
o Structural and functional unit of life
o Groups of cells similar in structure and function
o Two or more tissues work together towards a common greater function, each contributing the function of its cell type
Cells
Tissues
Organs
o Layers and lining
o Most abundant tissue in body, attachments, protection. Support and protection
Epithelial
Connective
o skeletal (control), smooth (involuntary), cardiac (heart). Movement and control o brain and spinal cord. Communication
Muscular
Skeletal
PROPERTIES OF A CELL:
Stem cell
o capable of becoming varied cells (unspecialized)
Ex.) hemocytoblast – can become an RBC/WBC or…
PROPERTIES OF A CELL:
Totipotent
in the embryo, the original 1-32 cells have the ability to differentiate to ALL of the different types of cells and tissues
o able to differentiate into many different cell types (but perhaps not all)
o process of change & specialization. Depends on environment in which cell is found
PROPERTIES OF A CELL:
Multi-potent
Differentiation
o Separates intracellular fluids from extracellular fluids
o Plays a dynamic role in cellular activity
o Intracellular: inside the cell
o Extracellular: outside the cell
Plasma Membrane
o scheduled or programmed death of a cell
o Ex.) stratified squamous cells of skin slough off
Apoptosis
o unscheduled death of cells
o Necrotic: dying tissue
Necrosis
o trophe = nourishment)
o Increase in SIZE of cells > tissues > organs
Hypertrophy
o Decrease in SIZE of cells > tissues > organs
Atrophy
o (plassein = to mold)
o Increase in number of cells
o Can be hormonal, compensatory or pathologic (tumours)
♣ Ex.) calluses, more RBC’s in anemia, uterine cells during pregnancy (estrogen)
Hyperplasia
o A change from one cell type to another but LESS differentiated
o Can be reversible if stimulus is removed
o Can become cancerous if not
Metaplasia
o New and abnormal development of cells ♣ Benign: no harm ♣ Malignant: causes harm o Metastasis: these new cells may dissolve the membrane separating one tissue (ex. skin) from another (ex. blood or lymphatic vessel) and then invade other areas of the body ♣ Ex.) stage 1-4 cancer ♣ Movement of neoplasia cells
Neoplasia
Every cell needs…
o To get: nutrients (fats, AA’s, glucose)
o To get rid of: wastes (ammonia, CO2)
o Protection – from changes in its immediate environment
o pH, temperature, concentrations of water and other dissolved substances
Body is made up of 3 parts
Cells, intercellular spaces, fluids
FIBRES:
(“net”) – fibres that form a mesh or web or net – think ‘filtering’.
o Found in lymph nodes, liver, spleen
Reticulin
FIBRES:
stretch, rebounding protein.. C02
o Allows deformations of tissues (Cartilage in ear)
Elastin
FIBRES:
25% of all human protein is _____
o Strength in tissues
Collagen
o Between cells
o Carries (5 things) O2, CO2, nutrients, other wastes, hormones
o Transparent fluid in lymphatic vessels
o If fluids accumulate in a tissue (between the cells)
Interstitial
Blood
Lymph
Edema
• Percent of water in sweat:
Males =
females =
newborns =
60%
55%
75%
o Heart pumps - creates pressure in fluid = _______
o As distance increases from the heart, __ decreases
o ____ drives fluid OUT OF blood vessels
Hydrostatic pressure (HP)
o _____ is exerted by various proteins in the blood – primarily albumins. ______ = movement of water from low concentration to high concentration
♣ Albumins are made in the liver, normally kept in blood and not excreted by the kidney
o Concentration in the blood tends to stay the same throughout system (unlike HP)
o Higher concentration in blood than in the interstitial space attracts water
o ___ tends to draw water INTO blood vessels
Osmotic Pressure
o Hormone that increases permeability of capillaries – fluid leaks out into tissues
o Alters permeability of tissue
Histamine
