3 Histology Flashcards
What are the Four tissue types?
Epithelial (cover), muscle (contract), connective (connect), nervous (conduct)
What are the special characteristics of epithelial tissue?
Highly cellular, polar, attached, avascular, innervated, high regeneration capacity
General characteristics of connective tissue:
Diverse: all contain cells, protein fibers, and ground substance
General characteristics of muscle tissue:
Contractile. Contractile response is stimulated by nervous and/or endocrine system
General characteristics of nervous tissue?
Two types: neurons and glial cells
Neurons are excitable, high metabolic rate, non-mitotic, have extreme longevity
Glial cells are not excitable and mitotic.
General functions of epithelial tissue?
Covers surfaces: lines body cavities and organs.
General functions of connective tissue?
Protection, connection, and support
General functions of muscle tissue?
Movement. Of skeleton or organ walls.
General fn nervous tissue?
Neurons: control activities and transfer information
Glial cells: support, protect, and provide energy for neurons
Germ layer of epithelium?
All. Ectoderm, mesoderm, and endoderm.
Germ of connective tissue?
Mesoderm
Germ layer of muscle tissue?
Mesoderm
Germ layer of nervous tissue?
Ectoderm
What are the functions epithelial tissue?
Physical protection, selective permeability, secretion, sensation.
What kinds of junctions hold together epithelial cells?
Tight junctions
Adhering junctions
Desmesomes
Gap junctions
What is the purpose of tight junctions and where do they appear?
They appear near apical surface sealing the circumference of epithelial cells and forcing transport of fluids and other molecules through their cellular membranes,
Purpose and location of adhering junctions?
Deep to the tight junctions. Sealed for a length. Designed for strength.
Desmesomes
Peptide connections that occur at single stress points to reinforce cell wall.
Gap junctions
Provide molecule/ion transport
What are cilia and where do they appear?
On apical surface of certain epithelial tissues. Motile. Move stuff along them. e.g. Smokers cough/mucous ladder in lungs.
What are microvilli and where do they appear?
They appear also on apical surface. Designed to increase surface area. e.g. Kidney tubules and small intestine.
What is the function of simple squamous epithelium and where is it found?
Fns: diffusion, filtration
Locations: alveoli, lining of blood vessels/capillaries, serous membranes
What are the functions of simple cuboidal and where can it be found?
Fns: absorption and secretion
Locations: thyroid gland, kidney tubules, ovary, and most endocrine and exocrine glands.
What are the functions of simple columnar and where is it found?
Fns: absorption, secretion, and movement ( often have cilia associated)
Locations: non-ciliated in stomach, bladder, and uterine tubes. With microvilli in small intestine.
What is function of stratified squamous and where is it?
Fn: protection
Location: lining of oral cavity, pharynx, esophagus, vagina and anus; also, epidermis.
What are the functions and locations of pseudostratified columnar epithelium?
Fns: movement and protection
Locations: respiratory tract (ciliated) and epididymis and male urethra (non ciliated)
What are the functions and locations of transitional epithelium?
Fn: distention and relaxation of urinary structures.
Locations: ureters, bladder, urethra
What are the two types of glands?
Exocrine and endocrine
What are the characteristics of exocrine glands and what types are there?
They have ducts and use them to secrete their product onto epithelial surface.
Types are holocrine, merocrine, and apocrine.
Merocrine glands?
Secrete via vesicle
e.g. Lacrimal, salivary, gastric, pancreatic, and eccrine sweat.
Holocrine glands?
Entire cell disintegrates and products are pushed out.
e.g. Sebaceous gland.
Apocrine glands?
Secrete via cell decapitation
e.g. Mammary glands, apocrine sweat glands
What are the different types of connective tissue?
Fluid connective tissue e.g. blood
Supporting connective tissue e.g. Bone/cartilage
Connective tissue proper subdivided into:
Loose connective tissue with fewer fibers and more ground substance e.g. Adipose, areolar,and reticular tissues
Dense connective tissue with more fibers and less ground substance e.g. Regular, irregular, and elastic tissues
What are the functions of connective tissue?
Physical protection e.g. Bone and cartilage
Support and structural framework e.g. Bone
Binding of structure e.g. Connective tissue proper and cartilage
Storage of calcium and fat e.g. Bone
Transport of nutrients, hormones, and gasses e.g. Blood
Immune protection e.g. Blood
What are the characteristics of CT tissue cells?
Cells are not in direct contact with each other
Float in an ECM (extra cellular matrix) of non living tissue.
What is e ECM made of?
Ground substance, which is composed of proteins, water, and carbohydrates
What is the function of ECM proteins and what types of fibers make them up?
They offer strength and support
Collagen, elastic, and reticular
What are the kinds of loose connective tissue and where are they found?
Areolar–surrounds blood vessels and nerves
Adipose–subcutaneous layer, surrounding organs
Reticular–inside lymphatic organs
What are the types of dense connective tissue and where is it found?
Regular, found in tendons and ligaments
Irregular, found in dermis of skin
Elastic, found in walls of large arteries
What is the cause and symptoms of scurvy?
Caused by vitamin C deficiency, which causes normal collagen fibers to not form, weakening structures of gums, teeth, bones, and internal mucosa. Wounds and fractures won’t heal.
What is the cause and symptoms of marfan’s syndrome?
Caused by genetic abnormality on chromosome 15, producing abnormal fibrillin, collagen, and elastin. Causes skeletal, vision, and cardiovascular abnormalities. Early death because of heart weakness.
What are the causes of gangrene and what are the varieties?
Injury, lack of blood flow, bacterial infection, or diabetes. Wet, dry, and gas gangrene.
