Histology - Anaphy and Physiology Laboratory Flashcards
is a group of structurally and functionally related cells and their external environment that together perform common functions
tissue
is the study of the normal structure of tissues
histology
Four tissue types in the adult human body:
- Epithelial tissue
- Connective tissue
- Muscle tissue
- Nervous tissue
covers and lines all body surfaces and cavities
Epithelial tissue
very widespread and performs binding, support, protection, and transport functions
Connective tissue
contracts and generates force
Muscle tissue
generates, sends, and receives electrical signals throughout the body
Nervous tissue
Each of the body’s organs is composed of
two or more tissue types
The innermost layer of the intestinal wall consists largely of _________________________ that secretes enzymes and absorbs nutrients
epithelial tissue
The small intestine, for example, contains
all four tissue types
The innermost layer of the intestinal wall consists largely of epithelial tissue that
secretes enzymes and absorbs nutrients
The second layer the intestinal wall consists of ___________________________________ that supports the epithelium and contains a rich supply of blood vessels that carry absorbed nutrients away from the small intestine
connective tissue
The second layer the intestinal wall consists of connective tissue that
supports the epithelium and contains a rich supply of blood vessels that carry absorbed nutrients away from the small intestine
The third layer consists of ________________________ which contracts to mix the intestinal contents and propel them toward the large intestine
smooth muscle tissue
The third layer consists of smooth muscle tissue which
contracts to mix the intestinal contents and propel them toward the large intestine
penetrating all the layers of the intestinal wall transmit sensory information from the small intestine to the CNS, and motor commands from the CNS to the smooth muscle layers
Nerve fibers
Nerve fibers penetrating all the layers of the intestinal wall
transmit sensory information from the small intestine to the CNS, and motor commands from the CNS to the smooth muscle layers
covers both internal body surfaces (such as the inner lining of the stomach) and external body surfaces (such as the skin).
EPITHELIAL TISSUE
- it also forms glands, such as sweat glands
EPITHELIAL TISSUE
performs a wide variety of functions, including transport (diffusion and active transport), secretion, and protection.
EPITHELIAL TISSUE
consists of tightly packed cells sitting on an adhesive, acellular structure called a basement membrane, which attaches it to underlying connective tissue.
Epithelium
an adhesive, acellular structure which attaches epithelium to underlying connective tissue
Basement membrane
Epithelial tissue is ______________—it has no blood supply of its own.
avascular
Epithelial tissue is avascular—
it has no blood supply of its own
Each epithelium has two basic characteristics:
- the number of cell layers
- the shape of its cells
Epithelia that have a single layer of cells
Simple Epithelia
Epithelia that have two or more layers
Stratified Epithelia
Epithelial cells are either:
- flattened (squamous)
- cube shaped (cuboidal)
- column shaped (columnar)
flattened
squamous
cube shaped
cuboidal
column shaped
columnar
Epithelia are named according to the
combination of cell shape and number of cell layers
A single layer of flattened epithelial cells
Simple squamous epithelium
Example is the air sacs in the lungs
Simple squamous epithelium
example of Simple squamous epithelium
air sacs in the lungs
A single layer of cube-shaped epithelial cells
Simple cuboidal epithelium
example of Simple cuboidal epithelium
kidney tubules
a single layer of column-shaped cells
Simple columnar epithelium
found in the small intestine.
Simple columnar epithelium
consists of two or more cell layers in which the basal cells are cuboidal or columnar, but the apical cells are flattened.
Stratified squamous epithelium
- those closest to the basement membrane
- are cuboidal or columnar
Basal cells
Stratified squamous epithelia are subdivided into two types:
- nonkeratinized
- keratinized
the outermost layer of cells is living
nonkeratinized stratified squamous epithelium
the outermost cells are dead and filled with the waterproofing protein keratin
keratinized stratified squamous epithelium
waterproofing protein
Keratin
Two or more layers of cube-shaped cells
Stratified cuboidal epithelium
whereas two or more layers of column-shaped cells
Stratified columnar epithelium
The number of layers directly determines the ______________ of epithelial tissue
function
The single cell layer of simple epithelia easily
permits passage of materials across it, so they are important in transport and secretion.
The many cell layers in stratified epithelia
provide protection against friction and abrasion
There are two unique examples of simple and stratified epithelia:
- Pseudostratified columnar epithelium
- Transitional Epithelium
consists of column-shaped cells of differing heights containing nuclei at different levels of the cells
Pseudostratified columnar epithelium
this epithelium appears to be stratified, but because every cell rests on the basement membrane, it consists of only a single layer of cells.
Pseudostratified columnar epithelium
Pseudostratified epithelium can be
ciliated or nonciliated.
Pseudostratified columnar epithelium can be found in
trachea
is a stratified epithelium found only in the urinary system
Transitional epithelium
the unique dome-shaped cells on its apical surface change shape according to the degree of stretch required of the structure in which they are found
Transitional epithelium
the apical cells in transitional epithrlium are ______________ when the structure is distended, and __________________ when the structure is empty
flattened; rounded (dome shaped)
is the body’s most widespread tissue type
CONNECTIVE TISSUE
consist of scattered cells embedded in an abundant extracellular matrix
CONNECTIVE TISSUE
is composed of a ground substance plus various types of protein fibers and ranges from a liquid (as in blood) to a solid (as in bone).
Matrix
Protein fibers include:
- collagen fibers
- elastic fibers
give the tissue strength and resist tension and pressure
collagen fibers
give the tissue flexibility
elastic fibers
provide a supporting network for the entire tissue.
reticular fibers
The various combinations of ground substance, protein fibers, and cells enable connective tissue to perform a large variety of functions:
binding, support, protection, and transport
Connective tissues can be divided into two groups:
- connective tissue proper
- specialized connective tissue
connective tissue proper
- loose connective tissue
- dense connective tissue
- reticular tissue
- adipose tissue
specialized connective tissue
- cartilage
- bone
- blood
Connective tissue proper contains four major types of cells:
- fibroblasts
- adipocytes
- macrophages
- mast cells
- The most prominent cells
- produce the protein fibers of the ECM
Fibroblasts
- fat cells
- filled with lipid droplets
- found in many different connective tissues
Adipocytes
Two specialized types of leukocytes:
- macrophages
- mast cells
phagocytic
Macrophages
function in inflammation
Mast cells
Connective tissue proper includes four types of tissue:
- Loose connective tissue
- Dense connective tissue
- Reticular tissue
- Adipose tissue
Loose connective tissue are also known as
areolar connective tissue
provides support and protection in the walls of hollow organs and membranes lining body cavities.
Loose connective tissue
consists of fibroblasts and all three types of protein fibers embedded in a gel-like ground substance, plus scattered macrophages, mast cells, and fat cells.
Loose connective tissue
primary component is protein fibers, which provide strength
Dense connective tissue
provide strength
protein fibers
The three types of dense connective tissue are:
- Dense regular
- Dense irregular (collagen fibers)
- Dense regular elastic (elastic)
- found in tendons and ligaments
Dense regular connective tissue
resists unidirectional stress because of the parallel arrangement of fibers
Dense regular connective tissue
found in the deep layer of thick skin and around joints
Dense irregular connective tissue
resists stress from every direction because of the haphazard arrangement of fibers
Dense irregular connective tissue
primarily contains elastic fibers
Elastic connective tissue
allows stretch and recoil in large blood vessels and certain ligaments
Elastic connective tissue
the fine network of fibers that forms the structure of many organs and supports small structures such as blood vessels and leukocytes
Reticular Tissue
is found in the spleen, liver, lymph nodes, and bone marrow
Reticular Tissue
adipose tissue consists primarily of
adipocytes
functions in insulation, warmth, shock absorption, and energy storage
adipose tissue
found deep to the skin; in the abdomen, breasts, hips, buttocks, and thighs; and surrounding the heart and abdominal organs
adipose tissue
perform more specialized functions than does connective tissue proper
Specialized Connective Tissues
functions in support, maintaining the shape of structures, and shock absorption
Cartilage
the major cells in cartilage are
Chondrocytes
The three types of cartilage are:
- hyaline cartilage
- fibrocartilage
- elastic cartilage
found in the trachea and between bones in joints
Hyaline cartilage
found between intervertebral discs
Fibrocartilage
found in the external ear and the epiglottis
Elastic cartilage
functions in support and protection
Bone
serves as attachment sites for muscles, produces blood, and stores fat and minerals
Bone
major cells of bones are
osteocytes
Blood contains three so-called “formed elements”:
- erythrocytes
- leukocytes
- platelets
- red blood cells
- transport oxygen
erythrocytes
- white blood cells
- function in immunity
leukocytes
function in blood clotting
Platelets
located in the brain, spinal cord, and nerves
Nervous Tissue
Nervous tissue contains two types of cells:
- neurons
- neurological cells
transmit electrical signals to, from, and within the central nervous system (the brain and spinal cord).
Neurons
their structure is highly adapted for sending and receiving electrical impulses.
Neurons
neurons have two types of cell processes:
- dendrites
- axons
receive and carry impulses toward the cell body
Dendrites
carry impulses away from the cell body.
Axons
Neuroglial cells are also referred to as
supporting cells
they support, anchor, monitor, nourish, and insulate neurons
Neuroglial cells
are unable to transmit electrical signals
Neuroglial cells
most neuroglial cells are unable to transmit electrical signals and are thus considered
nonirritable
There are three types of muscle tissue: (all of which are capable of contraction)
- Skeletal muscle
- Cardiac muscle
- Muscle cells (smooth muscle)
- attached to bone
- are long and cylindrical, multinucleate, and surrounded by a thin connective tissue sheath called endomysium
Skeletal muscle
skeletal muscle appear striated (striped) due to the particular arrangement within them of the contractile myofilaments ______________________
actin and myosin
skeletal muscle are under
voluntary control
thin connective tissue sheath
Endomysium
- found only in the heart
- are short, branched, typically uninucleate cells that are interconnected by intercalated discs and surrounded by endomysium.
Cardiac muscle
cardiac msucle are striated but
not under voluntary control
are thin, uninucleate, tapered cells that lack striations
Smooth muscle
smooth muscle are
not voluntarily controlled
