Exam II Flashcards
Define: tissue
A group of cells with a common structure and function
Histology
The study of tissues and their structures at the microscopic level.
Ectoderm:
Outer germ layer
-gives rise to epidermis, NS, exocrine glands
Endoderm
Inner germ layer
-forms mucous mem in digestive & respiratory tracts, digestive glands
Epithelial tissue
tissue that covers the body, line cavities and forms glands. protective barrier, absorption, secretion and sensation
polarity
has distinct atipcal and basal surfaces w diff func.
Intercellular Attachment:
Cells are tightly connected by junctions like tight junctions and desmosomes.
-hemidesmosomes
Avascularity
lacks blood vessels
high regeneration
rapidly replaces cells
Functions of Epithelial Tissue
protection, selective permeability, sensation & secretions
Classifying Epithelial Tissue:
By # of cells
Simple: Single layer of cells.
Stratified: Multiple layers of cells.
Pseudostratified: Appears to have multiple layers but is a singular layer
Epithelial cell shapes
Squamous: Thin and flat cells.
Cuboidal: Cube-shaped cells.
Columnar: Tall, column-like cells.
Transitional: Cells that can change shape, found in tissues that stretch.
Cilia:
Hair-like projections that move substances across the cell surface.
Microvilli:
finger-like projections that increase surface area for absorption.
Simple Epithelium
single layer of cells; functions in absorption, secretion, and filtration
Stratified Epithelium:
Multiple layers of cells; functions in protection, found in areas prone to abrasion.
Pseudostratified Epithelium:
Appears layered but is actually a single layer. involved in secretion and movement of mucus.
Exocrine glands
conn. w epithelium by ducts
-apocrine, holocrine, merocrine
Endocrine glands
Release hormones directly into bloodstream w/o ducts (thyroid/adrenal)
Serous secretions
Watery fluids rich in enzymes (saliva)
Sebaceous secretions
oily substances to lub and protect skin (sebum)
keratinized
superficial cells are dead
non-keratinized
superficial cells are living
merocrine secretion
Secretion released via exocytosis (sweat, salivary) produced in golgi
apocrine secretion
apical mem pinches off & becomes secretions (mamm/milk & ceruminous glands/ earwax) damage repaired by glandular cells
holocrine secretion
secretions released by cells bursting/killing gland
-sebaceous gland
-gland replaced by stem cells
ground substance
gel-like substance found in connective tissue that fills space btw cells and fibers (GS + protein fibers= extracell matrix)
Mesenchyme:
found in embryos, ALL CT is from this
connective tissue proper
loose: areolar, adipose, reticular (more GS)
dense: dense reg, dense irreg, elastic (less GS)
supporting CT
Cartilage: hyaline, fibrocartilage, elastic
bone: compact, spongy
fluid CT
blood & lymph
areolar CT
ctp. loose arrangement of collagen & elastic fibers, vascular
-blood vessels
adipose CT
ctp. adipocytes aka fat, stores energy, insulates body.
-white- stores energy
brown-babies/gen heat
reticular CT
ctp. meshwork of reticular fibers, fibrocytes & leukocytes
-lymphatic organs
Dense Reg CT
ctp. tightly packed, PARALLEL fibers, stress in 1 direction
-tendon/ligaments
Dense Irreg CT
ctp. clumps of collagen in all directions, stress in all dir.
-found in reticular layer (dermis)
Elastic CT
ctp. branching, densely packed, can stretch & recoil
-trachea
perichondrium
dense irreg ct that surr. elastic and most hyaline cartilage
Hyaline cartilage
sct. common, surr. perichondrium, found in nose/trachea, costal, fetal skeleton
Fibrocartilage
sct. weight-bearing, resist compression, irreg protein fibers btw chondrocytes, spare gs, no perichondrium, knee, intervertebral discs
elastic cartilage
sct. flexible, densely packed elastic fibers, external ear
Hemopoietic cells
make RBCs
Blood
fluid ct, transports cells, dissolves matter, plasma=GS
Lacunae:
cavities within the cartilage matrix that have chondrocytes
Fibroblasts
star-shaped, long nuclei, produce & maintain GS
Adipocytes
large, round cells, stores triglycerides
Mesenchymal cells
divides to replace cells, embryonic stem cells
macrophages
fixed & wandering: eat pathogens and debris
mast cells
found in blood vessels, release histamine & heparin, inflammation/allergic reactions
plasma
synthesize disease fighting antibodies
leukocytes
WBCs: neutrophils- attack bacteria
lymphocytes react against bacteria/toxins
cardiac muscle
-heart
1 nucleus, striated, invol, branched
smooth muscle
NO striations, 1 nucleus, fusiform cells (thick in middle, tappered on sides). invol
-digestive, respiratory, urinary tract
skeletal muscle
voluntary, striations, attached to bone, thread-like muscle fibers
Binds organs to each other
-supports and protects
Areolar tissue
Primary germ layers
Ectoderm, exoderm, mesoderm
Mesoderm
middle germ layer
-becomes mesenchyme
-forms ALL CT
-forms epithelial lining of vessels & serous mem
Epithelial lining
Endothelium (lines vessels) & mesothelium (serosa)
Basement membrane
Layer btw epithelium & underlying connective tissue
3 attachments to BM
lamina lucida, lamina densa, reticular lamina
3 attachments to BM
lamina lucida, lamina densa, reticular lamina
Basal surface
Surface of an epithelial cell that faces BM
