Histology Flashcards
what are the 4 basic tissue types?
epithelial, connective, nervous, muscle
epithelial tissue
covers body surfaces and line body cavities, forms glands.
connective tissue
contains large amounts of extracellular matrix, provides physical support
nervous tissue
transit information via electrical signals
muscle tissue
generate mechanical force and movement via contraction
T/F: most organs contain all four types of tissues
TRUE
what are considered the building blocks of organs?
tissue
lining epithelium
sheets of cells that cover the body surface (skin) and lines body cavities (digestive and respiratory systems)
glandular epithilium
fors most body glands like salavary glands and mucus glands.
where do you normally see epithelial tissue?
at the boundary between two different environments
what are the functions of epithelial tissue?
- protection of underlying tissue
- secretion
- absorption
- diffusion
- filtration
- sensory reception.
what are the characteristics of epithelial tissue?
- high degree of cellularity
- specialized junctions between adjacent cells
- polarity
- support by underlying connective tissue
- avascular but innervated
- highly regenerative
what is epithelial tissue classification based on?
cell shape and number of cell layers
basal surface
layer where new daughter cells are created (most important layer)
what are the 8 types of epithelium?
- simple squamous epithelium
- simple cuboidal epithelium
- simple columnar epithelium
- pseudo-stratified epithelium
- stratified squamous epithelium
- stratified cuboidal epithelium
- stratified columnar epithelium
- transitional epithelium
simple squamous epithelium
single layer of flattened cells with disc shaped central nuclei and sparse cytoplasm.
what is the simplest form of epithelia?
simple squamous epithelium
what is the function of simple squamous epithelium?
diffusion, filtration, secretion and absorbtion
where would simple squamous epithelium be found?
- kidney glomeruli
- alveoli (air sacs of the lungs)
- lining of the heart, blood vessels, lymphatic vessels
- lining of the ventral body cavity (serosae)
what is the function of simple cuboidal epithelium?
secretion and absorption
simple cuboidal epithelium
simple layer of cubelike cells with large spherical nuclei
where would simple cuboidal epithelium be found?
- kidney tubules
- ducts and secretory portions of small glands
- ovary surface
simple columnar epithelium
single layer of tall cells with round/oval nuclei; some cells may have cilia; layer may contain mucus secreting unicellular glands (goblet cells)
what is the function simple columnar epithelium?
- absorption
- secretion of mucus, enzymes and other substances
- ciliated types propel mucus by ciliary action
where would simple columnar epithelium be found?
Non ciliated:
- lines most digestive tract (stomach to anus tract)
- small intestine
- gallbladder
- excretory ducts of some glands.
Ciliated:
- lines small bronchi
- uterine tubes
- some regions of uterus
what kind of tissue contains microvilli?
simple columnar epithelium
microvilli
fingerlike extensions of the apical plasma membrane that contains a supportive core of actin that is connected to cells cytoskeleton
what does microvilli do?
increase surface area
what disease is caused by the destruction of simple columnar epithelium?
inflammatory bowel disease (crohns disease)
pseudo-stratified columnar epithelium
Single layer of cells of differing heights (some not reaching the free surface); nucleus is seen at different levels; may contain secreting-goblet cells and bear cilia.
what is the function of pseudo-stratified columnar epithelium?
- secretion (mostly mucus)
- propulsion of mucus by ciliary action
where would pseudo-stratified columnar epithelium be found?
Non ciliated:
- male sperm carrying ducts
- ducts of large glands
Ciliated:
- upper respiratory tract
- lines trachea
what kind of epithelium contains cilia?
pseudo-stratified columnar epithelium
cilia
contains 9 pairs of microtubules (doublets) surrounding 1 central pair.
what is cilia connected to to help aid in movement?
motor protein called dynein
why do chronic smokers constantly cough up mucus?
because their cilia is damaged
stratified squamous epithelium
thick membrane composed of many layers of cells; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened; in keratinized type the surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers
what is the function of stratified squamous epithelium
protects underlying tissues in area subjected to abrasion
where would stratified squamous epithelium be found?
Non keratinized:
- moist lining of esophagus
- mouth
- vagina
keratinized:
- forms the epidermis of the skin
- a dry membrane
how is GERD caused?
Damage to your esophageal sphincter which causes gastric acid flowing from your stomach back up into your esophagus.
what tissue is damaged that results in GERD
stratified squamous epithelium
Stratified cuboidal epithelium
generally two layers of cubelike cells
what is the function of Stratified cuboidal epithelium
protection
where would Stratified cuboidal epithelium be found?
- largest ducts of sweat glands
- mammary glads
- salivary glands
stratified columnar epithelium
several cell layers; basal cells usually cuboidal; superficial cells elongated and columnar
what is the function of Stratified columnar epithelium
protection and secretion
where would Stratified columnar epithelium be found?
- small amounts in the male urethra
- large ducts of some glands
what type of epithelium is rare in the body?
stratified columnar epitheium
transitional epithelium
resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamous like depending on degree of organ stretch.
what is the fuction of transitional epithelium?
permits stretching when needed
where would transitional epithelium be found?
lines the uterus, bladder and parts of the urethra
what do cell junctions do?
link cells to each other in tissues, and regulate tissue homeostasis
what does the basement membrane do?
anchors the epithelia with the underlying conncetive tissue
what does the basal membrane consist of?
basal lamina and reticular lamina (layer of reticular fibers)
what are the reticular fibers in the reticular lamina produced by?
areolar connective tissue
endocrine glands
secrete products into the circulatory system
what are some examples of endocrine glands?
pituitary gland, thyroid gland, pancreas
exocrine glands
secrete products onto body surfaces or into body cavities via ducts
what are examples of exocrine glands?
sweat glands, sebaceous glands, mammory glands, pancreas
what gland uses a simple tubular duct?
intestinal glands
what gland uses a simple branched tubular duct?
gastric glands
what gland uses a simple alveolar duct?
no important example in humans (frogs and fish)
what glad uses simple branched alveolar ducts?
sebaceous glands
what gland uses compound tubular ducts?
duodenal glands of the small intestine
what glands use compound alveolar ducts?
mammary glands
what glands use compound tubuloalveolar ducts?
salivary glands
what is the function of connective tissue
support, connect adjacent tissues, stores nutrients, and immunity
what are characteristics of connective tissue?
few amount of cells but lots of extracellular matrix.
where does all connective tissue originate from?
embryonic mesenchyme
what kind of cells are found in connective tissue?
- fibroblasts
- chondroblasts and chondrocytes
- osteoblasts and osteocytes
- adipocytes
- erythrocytes and leukocytes
- mast cells
what is ground substance? what does it do?
Gel like substance that holds water and varies among connective tissue types. Responsible for providing protection and resisting compression
what fibers are found in connective tissue?
collagen, reticular, elastic
what is the function of collagen fibers?
strongest fiber and resist tension (allows for stretching)
what is the function of reticular fibers?
mesh-like network responsible for support (scaffolding)
what is the function of elastic fibers?
strong recoil ability
mesenchyme
embryonic connective tissue; gel-like ground substance containing fibers; star shaped mesenchymal cells
where is the mesenchyme usually found?
primarily in the embryo
areolar connective tissue
loose connective tissue; gel-like matrix with all three fibers types; consists of fibroblasts, macrophages, mast cells and some white blood cells.
adipose connective tissue
loose connective tissue; same matrix as areolar connective tissue, bust very sparse; closely packed adipocytes, have nucleus pushed into the side by fat droplet.
what is the function of adipose connective tissue
provides reserved food fuel, insulation, support and protection of organs
where would adipose connective tissue be found?
under the skin in the hypodermis; around the kidneys and eyeballs; within abdomen; in breasts
reticular connective tissue
loose connective tissue; network of reticular fibers in a typical loose ground substance; reticular cells lie on the network
what is the function of reticular connective tissue?
fibers form a soft internal skeleton that supports other cell types including white blood cells, mast cells and macrophages
where would reticular connective tissue be found?
lymphoid organs (lymph nodes, bone marrow, and spleen)
dense irregular connective tissue
dense connective tissue; mostly irregularly arranged collagen fibers and some elastic fibers; major cell type is fibroblasts; defense ells and fat cells are also present.
what is the function of dense irregular connective tissue?
able to withstand tension exerted in many directions; provides structural strength
where would dense irregular connective tissue be found?
fibrous capsules of organs and joints; dermis of the skin; submucosa of digestive tract
dense regular connective tissue
dense connective tissue; mostly parallel collagen fibers and few elastic fibers; majority of the cell type is fibroblasts
what is the function of dense regular connective tissue?
attaches muscles to bone or to muscles; attaches bone to bone; withstands great tensile stress when fulling force is applied in one direction
where would dense regular connective tissue be found?
tendons, most ligaments, aponeuroses
dense elastic connective tissue
dense regular connective tissue containing high proportion of elastic fibers
what is the function of dense elastic connective tissue?
allows recoil of tissue following stretching; maintains pulsatile flow of blood through arteries; aids in passive recoil of lungs following inspiration
where would dense elastic connective tissue be found?
walls of arteries; within certain ligaments associated with the vertebral column; within walls of bronchial tubes
hyaline cartilage
most common; amorphous but firm matrix; collagen fibers form impermeable network; chondroblasts produce the matrix and when mature lie in lacunae
whats a mature chondroblast called?
chondrocyte
what is the function of hyaline cartilage?
supports and reinforces; serves as resilient cushion; resist compressive stress
where would hyaline cartilage be found?
forms most of the embryonic skeleton; covers ends of long bones in joint cavities; forms costal cartilage of the ribs; cartilage of the nose, trachea, and larynx
how is osteoarthritis formed?
simple wear and tear of hyaline cartilage resulting bone on bone.
elastic cartilage
similar to hyaline cartilage but more elastic in matrix
what is the function of elastic cartilage?
maintains the shape and structure while allowing flexibility (stretch and recoil)
where would elastic cartilage be found?
supports the external ear; epiglottis
fibrocartilage
matrix is similar but less firm than the hyaline cartilage; thick collagen fibers are predominate
what is the function of fibrocartilage?
tensile strength with ability to absorb compressive shock
where would fibrocartilage be found?
intervertebral discs; pubic symphysis; discs of knee joint
bone
connective tissue; hard calcified matrix containing many collagen fibers; osteocytes lie in lacunae; very well vascularized
what is the function of bone?
- supports and protects
- provides levels for muscles to act on
- stores calcium and other nimerals and fats
- marrow inside bones is the site for blood cell formation
hematopoiesis
the process of creating a wide variety of blood and bone marrow cells
what is the function unit of the cortical bone?
osteon
compact bone
a hard, solid osseous tissue found in the cortex of all bones.
spongy bone
Spongy bone is softer than compact bone. Spongy bone is composed of branches of trabeculae. Spongy bone is lighter in weight than compact bone. Spongy bone receives nutrients through osteons.
blood
connective tissue; red and white blood cells in a fluid matrix (plasma)
what is the function of blood?
transport respiratory gases, nutrients, wastes and other substances
covering and lining membranes are composed of both ________ _________ and underlying _______ ________.
epithelial tissue, connective tissue proper
lamina propria
thin layer of areolar tissue which lies beneath the epithelium of mucous membranes
cutaneous membrane
the membrane that covers the body surface (skin)
serous membrane
lines the body cavities that are closed to the exterior
mucous membrane
lines body cavities that are open to the exterior
what does nervous tissue consist of?
neurons and supporting cells (neuroglia)
sensory/afferent neurons
receive signals from the environment via receptors
motor/efferent neurons
send signals to effectors
what is the function of nervous tissue?
transmit electrical signals from sensory receptors and to effectors that control the activity of the effecter organs
where is nervous tissue found?
brian, spinal cord and nerves
what types of neuroglia are in the central nervous system?
ependymal cells, oligodendrocytes, astrocytes, microglia
what types of neuroglia are in the peripheral nervous system?
satellite cells and Schwann cells
ependymal cells
lines the ventricles of the brain and central canal of spinal cord and secretes spinal fluid
oligodendrocytes
wrap myelin on the axons of neurons in the CNS
astrocytes
contributes to the blood brain barrier; acts as a gatekeeper
microglia
immune cells in the central nervous system
satellite cells
cover the dorsal root ganglion
Schwann cells
wrap myelin on the axons of neurons in the PNS
T/F neurons can be some of the longest cells?
TRUE
3 types of muscle tissue?
cardiac, smooth, and skeletal
cardiac muscle
branching, striated, generally uninucleate cells, consist of intercalated disks
what is the function of cardiac muscle
as it contracts it propels blood into the circulation; involuntary control
where is cardiac muscle located?
the walls of the heart
smooth muscle
spindle shaoed cells with central nuclei; no striations; cells arranged closely to form sheets
what is the function of smooth muscel
propels substances or objects (food, urine, baby) along the internal passageways; involuntary control
