Tissues Flashcards
What do tissues form?
Organs
4 types of tissues
Epithelial, connective, muscle, nervous
What gives rise to the tissue types?
Primary germ layers
What are the primary germ layers from outside to inside?
Ectoderm, mesoderm, endoderm
Which organs/parts are derived from the ectoderm?
Nervous system, skin epidermis, cornea/lens, enamel, adrenal medulla, pituitary and pineal gland.
Which organs/parts are derived from the mesoderm?
Musculoskeletal system, urinary system, muscular layer of digestive system, circulatory system, lymphatic system, skin dermis, reproductive system (except for germ cells), adrenal cortex
What organs/parts are derived from the endoderm?
Epithelial linings, liver, pancreas, thyroid gland, thymus, parathyroid glands
What systems are lined by epithelial cells derived from endoderm?
Digestive system, respiratory system, urinary system, reproductive system
Humor
Bodily fluids of animals
Types of humor
Intracellular and extracellular
What are the two types of extracellular fluid?
Interstitial (in ECM) and plasma
Features of epithelial cells
Attached to basal lamina, no blood vessels (avascular), regenerates, polarity allows for defines apical and basal membranes
Functions of epithelial tissue
Protection, regulates substance permeability, mediates sensations, secretes mucus, oil, tears, etc
4 methods of connection between epithelial cells
Gap junctions, tight junctions, desmosomes, adherens junctions
Tight junctions features
Seals together cells using proteins
Adherens junctions
Seals together cells by binding to actin microfilaments
Desmosomes
Mechanically supports cells using intermediate filaments
Gap junctions
Very permeable, important for electric charge conduction
What does the basal lamina consist of
Lamina lucida (top layer) and lamina densa (bottom layer)
What are the functions of the basal lamina
Anchoring epithelial cells, transition bw epithelial and connective tissue
3 different shapes of epithelial tissues
Squamous, cuboidal, and columnar
What are the classifications of epithelial tissues based on number of cell layers?
Simple = 1 layer, stratified = 2+ layers
Location of simple squamous epithelial
Mesothelium (lining of pericardium), kidney tubules, lung alveoli (gas exchance), endothelium (inner layer) of blood vessels
What is the simple squamous epithelial tissue specialized for and why?
Specialized for transportation, best for it because shorter diffusion distance due to only 1 cell layer = more efficient transportation
Types of stratified squamous epithelial tissue
Non-keritanized - mucosa (inner part, moist), keritanized - epidermis (dry, cells dead at maturity, protects against dehydration)
Function of stratified squamous epithelial tissue
Protection from mechanical damage, pathogens, and chemicals
Location of keratinized stratified squamous epithelial tissue
Exposed, outer surfaces
Location of nonkeratinized stratified epithelial tissue
Inner surfaces, mouth, esophagus, anus, vagina
simple cuboidal epithelial location
kidney tubules, pancreas, thyroid glands, salivary glands
Function of simple cuboidal epithelial location
secretion and absorption
What subcellular organelle is responsible for attracting a basic stain
Rough er
The pancreas has what types of functions
Endocrine and exocrine
What types of cells are islets of langerhans
Pancreas cells
What are the 3 main endocrine cell types
Alpha, beta, delta
What do alpha cells release
Glucagon
What do beta cells release
Insulin
What do delta cells release
Somatostatin
Function of stratified cuboidal epithelium
Secretion and absorption
Location of stratified cuboidal epithelium
Sweat and mammary glands
Transitional epithelium location
Urinary bladder and ureters
Structure of transitional epithelium when relaxed
Stratified cuboidal epithelium
Structure of transitional epithelium when stretched
squamous epithelium
Functions of transitional epithelium
tolerates stretching
Structure features of simple columnar epithelium
- Nuclei near basal lamina
- Apical surface has microvilli
- Immediately above the lamina propria connective cells
Location of simple columnar epithelium
Stomach, intestine, gallbladder, collecting ducts of kidneys, uterine tubes
Function of simple columnar epithelium
Absorption and secretion
structure of pseudostratified columnar epithelium
No multiple layers, all cells contact basal lamina, all may not reach apical surface causing stratified appearance
What does pseudostratified mean
looks stratified, is actually simple, as all cells contact basal lamina
Location of pseudostratified columnar epithelium
Respiratory tract, male reproductive tract, fallopian tubes
Function of pseudostratified columnar epithelium
Moves materials across surface
Features of stratified columnar epithelium
Rare, 2+ layers but only apical layer is columnal for protection
Function of stratified columnar epithelium
protection
Location of stratified columnar epithelium
Salivary glands, pharynx, mammary glands, urethra, anus
Differences between endocrine and exocrine
endo releases secretions/hormones into bloodstream; exo releases other secretions like sweat, other enzymes into ducts
Glandular epithelium
Epithelial tissues involved in production and release of secretory substances
Modes of secretion
Merocrine, apocrine, holocrine
Merocrine secretion
Product released from vesicles via exocytosis (ex: goblet cells, sweat glands)
Apocrine
Apical region with vesicles is shed to release products (ex: mammary gland)
Holocrine
Entire cell is lysed/blows up to release product, secretory cell dies (ex: oil glands)
Types of secretion
Serous, mucous, mixed exocrine glands
Serous glands
Releases water and enzymes (ex: parotid salivary glands)
Mucus glands
Mucin+water = mucus, (ex: goblet cells)
Connective tissue features
Never exposed to environment, well vascularized, cells + matrix
What makes up the matrix
Fibers + ground substance
What are the 3 fiber types
Collagen, reticular, and elastic
What is ground substance
Gel like fluid made of interstitial fluid, cell adhesion molecules, and glycosaminoglycans
Cells where connective tissue is common
Fibroblasts (produce matrix), mesenchymal (type of stem cell), adipocytes (fat cells), phagocytes, lymphocytes (B and T cells), mast cells
What are collagen fibers made of
Collagen type 1
What are reticular fibers made of
collagen type 3
What are elastic fibers made of
Elastin
Function of connective tissues
Structural support, portection, circulation of fluids and dissolved substances, food storage and thermoregulation, immune defense
Connective tissue is derived from
Mesynchyme
Mesynchyme is derived from
Mesoderm
What does mesoderm give rise to
Blood, lymph, bones, and muscles
What gives rise to ectomesenchymal cells
Ectodermal natural crest
3 types of connective tissues
Connective tissue proper, fluid connective tissue, supportive connective tissue
2 types of connective tissue proper
Loose, dense
3 types of loose connective tissue
Areolar connective tissue, adipose, tissue, reticular tissue
Functions of areolar tissue
Absorb shock, resists distortion, fills space bw cells
Adipose tissue types
white and brown fat
Which type of fat is responsible for nonshivering thermogenesis
Brown fat
Reticular tissue function
Structural support of parenchyma cells
Parenchyma function in organ
Performs main organ function, entirely functional cell, not structural
Name for macrophages in the liver
Kupffer cells
What are the three types of dense connective tissue
Dense regular, dense irregular, and elastic connective
Ligaments connect
Bone to bone
Tendons connect
Muscle to bone
Where is dense regular found
Tendons, ligaments, muscle coverings
Difference between structure of dense regular and irregular
Regular is parallel collagen fibers (Better for back and forth attachment), irregular is mesh of fibers
Function of dense irregular
Resists tension
Locations of elastic connective
Arterial walls, ligaments bw vertabrae
What is fluid connective tissue made of
Blood and lymph
What does plasma becomes lost in the blood bw cells
Interstitial fluid
What happens to interstitial fluid when it’s reabsorbed by the lymphatic system
Becomes lymph
3 coats of a blood vessel
Tunica intima, tunica media, tunica adventitia
What is tunica intima consisted of
Endothelial lining, basement membrane
What is tunica media made of
Smooth muscle layer
What is the tunica adventitia/externa composed of
Longitudinal connective tissue
Structural difference bw artery and vein
Artery more circular, thick wall and small lumen, veins have thin wall and broad lumen, often collapsed lumen
What is the thickest coat in the artery
Tunica media
Thickest coat in a vein
Tunica externa
What is a feature of arteries
Elastic internal membrane for recoil
What are the 3 types of arteries
Elastic, muscular, arterioles
Function of vasa vasorum
Mini blood vessels for the larger blood vessels for nourishment
Features of elastic artery
Blood straight from heart requires elastin abundance to stretch to accomodate walls to maintain blood pressure
Features/functions of muscular arteries
Distribute to larger femoral or coronary arteries, has endothelium
Atherosclerosis definition
Fat build up causing narrowing of arteries
What do some veins have
Valves
Why is the lumen larger in veins
Large diameter allows more blood to flow with less resistance
Types of capillaries
Continuous, fenestrated, discontinuous/ sinusoidal
Arteries ____ while veins do not
pulsate
Why can the venous system withstand lower blood pressure
Because it’s farther away from the heart
Where are continuous capillaries found + features
Muscle, CNS, lungs, least permeable capillary
Where are fenestrated capillaries found + features
Endocrine glands, gallbladder, intestinal tract, gaps bw endothelial cells continuous basal lamina
Where are discontinuous capillaries + features
Spleen, bone marrow, liver, large gaps bw cells
Two types of supportive connective tissue
Cartilage and bone/osseous
Function of supportive connective
Structural support and movement, provides shape
What kind of cells are cartilage composed of
Chondrocytes
Structure of cartilage
Avascular
Types of cartilage
Hyaline, elastic, fibro
Function of hyaline cartilage
Stiff but flexible support, minimizes friction between bones
Function of elastic cartilage
Resilient but flexible support
Function of fibrocartilage
Resists compression, absorbs shock
Types of bone tissue cells
osteocytes, osteoblasts, osteoclasts
Composition of bone tissue
Matrix, cells, periosteum
What is the bone tissue matrix made of
Calcium salts and collagen
Function of bone tissue
Support and protection, movement, stores minerals
3 types of muscle tissues
Skeletal, cardiac, smooth
Location of skeletal muscle tissue
All voluntary muscles
Function of skeletal muscle
moves bone, guards entrances/exits, produces heat via shivering thermogenesis
Cardiac muscle cells
Cardiomyocytes
Location of cardiac muscles
Heart muscle (myocardium)
Location of smooth muscle tissue
Walls of blood vessels and other hollow organs
Function of smooth muscle tissue
Transport through organs and involuntary movements
