Histology (Ch 4) Flashcards
What are the four types of tissues in the human body?
- Epithelia
- Connective
- Muscle
- Neural
What is epithelial tissue? (basic)
- layers of cells that cover body surfaces/line a body cavity
- on outside/inside of an organ
- sheet of cells at a boundary
What are the functions of epithelial tissue?
- Protection
- Gate-keeping- passage of material in and out
- Secretion- glands
- Sensory Reception- have nerves
What is simple epithelial tissue?
- single layer of cells
- typically in protected areas of body
- specialized for secretion/absorption
- -> found in air sacs of lungs, intestines, blood vessels
What is stratified epithelial tissue?
- multiple layers of cells
- found in areas subjected to wear
- -> found in vagina, esophagus, palm of hand
- named according to the cell shapes at the top surface
Simple Squamous Epithelium
- thin/flat –> gas exchange (diffusion/filtration)
- alveoli of lungs, capillary beds, lining of heart/blood vessels
Stratified Squamous Epithelium
- function: protect against abrasion
- typically found where mechanical stresses are severe
- ->surface of skin, mouth, esophagus, anus
keratinized vs. non-keratinized
keratinized: dryer environment, composed of dead cells on surface (ex. palm)
non-keratinized: may dry out (ex. mouth, vagina)
Simple Cuboidal Epithelium
- function: secretion/absorption
- -> kidney tubules, surface of ovaries, glands
Stratified Cuboidal Epithelium
- function: protection/secretion
- -> ducts of sweat glands and in mammary glands
Simple Columnar Epithelium
- function: absorption/secretion
- may be ciliated or have microvilli
- -> stomach, small intestine, large intestine, uterine tubes
cilia
hairlike projections found on apical surface of epithelia,
–> most found in bronchial tubes to move mucus from lungs to throat
microvilli
tiny, cytoplasm projections on cells apical surface that increase surface area for absorption/secretion
-appear fuzzy under microscope
(Ciliated) Pseudostratified Columnar Epithelium
- function: secretion, population of mucus w/cilia
- found along most of respiratory tract (nasal cavity, bronchi, trachea)
Stratified Columnar Epithelium
- rare
- function: protection/excretion
- -> portions of male urethra
What is Connective Tissue? (basic)
- fills internal spaces
- provides structural support for other tissues
- transports materials within body
- stores energy
What are the characteristics of Epithelial Tissue?
- supported by CT
- have apical (free) and basal (fixed) surfaces
- avascular (nutrients gained from apical and basal surfaces), but innervated (nerves but no blood vessels)
- regenerative, replace lost cells quickly b/c of mitotic division
What are characteristics of Connective Tissue?
- few cells
2. lots of extracellular matrix (ground substance + fibers)
What is ground substance?
part of CT extracellular matrix
-secreted by cells, functions as cushion/support, may be gel-like or hard
What are the protein fiber types of CT extracellular matrix?
- Collagen: strong/flexible, resist pulling, most abundant
- Elastic: rubber band, allows for stretching, thin
- Reticular: mesh-like, thinnest, form interwoven framework, tough but flexible, physically supports organs
What is a tissue?
groups of cells of similar structure that work together to perform a common function
What are the functions of Connective Tissue?
- Structural framework for body (holds things together)
- Transports fluids/dissolved materals (ex. nutrients/wastes –> blood)
- Protects organs, supports blood vessels/nerves
- Supports, surrounds, and is interconnected with other types of tissues
- Stores energy reserves (ex. fat)
- Defends body from infection
What are the divisions of connective tissue?
- CT Proper: many types of cells and extracellular fibers in a ground substance (loose/dense)
- Bone: structure/support
- Cartilage: structure/support
- Blood: fluid, RBC, WBC, carry nutrients, fight infection
What is Loose Connective Tissue? Types?
fibers widely spaced in ground substance
- Areolar
- Adipose
- Reticular
Loose Connective Tissue: Areolar
- -> widespread, least specialized
- loose organization, mix of all three fibers
- found beneath most epithelial tissue, surrounds most small nerves/blood vessels
- functions: supports/binds other tissues, holds body fluids, defends against infection, stores nutrients
Loose Connective Tissue: Adipose
- -> made of fat cells (adipocytes)
- stores nutrients, pads, absorbs shock, insulates
- located below dermis in Sub Q, in body cavities, and surrounding organs
Loose Connective Tissue: Reticular
- -> only reticular fibers + cells
- forms a scaffold to support other tissue/cell types
- found in spleen, bone marrow, and LN
What are the Dense Connective Tissue types?
- Regular
- Irregular
- Elastic
What is Dense Connective Tissue (Regular)?
- -> have collagen fibers packed tightly together, organized
includes: - tendons: attach skeletal muscle to bones
- ligaments: attach bone to bone
- aponeurosis: thin, sheet-like tendons that attach flat muscle to another muscle or several bones
What is Dense Connective Tissue (Irregular)?
- -> have collagen fibers with NO consistent pattern
- strengthen/support areas subject to stresses from many directions (dermis, periosteum - over bone)
- found in fibrous capsule around organs such as liver, kidneys, spleen, bon, and joint cavities
What is Dense Connective Tissue (Elastic)?
- -> dominated by elastic fibers, stretchy
- found in walls of elastic arteries (aorta) and respiratory passageways (trachea)
What is Muscular Tissue? (basic)
three types of muscle cells that contract to create movement
What is Neural Tissue? (basic)
specialized for the conduction of nervous impulses, in brain/spinal cord
What is Marfan Syndrome?
autosomal dominant disorder that affects connective tissues
- symptoms: long arms/legs/fingers, concave chest, flexible joints
- risk of death due to aortic dissection
What are glands? Types?
epithelial tissues that secrete a product
- endocrine: secrete directly into tissue around them, have NO duct (ex. pancreas)
- exocrine: secrete onto body surfaces/cavities, have a duct (ex. sweat, mammary)
