Star points test #1 Flashcards
definition of tissues
group of cells of similar structure that perform a common function.
four basic types of tissues
epiethelium, connective, muscle, nervous
functions of epithelial tissue
lining of surfaces
functions of connective tissues
- connecting tissues and organs
- form the basis of the skeleton,
- store and carry nutrients,
- surround all the blood vessels and nerves,
- lead the immune system.
function of muscle tissue
movement
functions of nervous tissue
communication
tight junctions
-form the closest contact between adjacent cells known in nature.
-so tight that some proteins in the plasma membrane are fused.
-Found in the apical region around the cell’s circumference, like a belt.
-these prevent molecules from passing.
(plays a role in secondary immune response because antigens ‘tighten’ the cell junction.)
desmosomes
- localized adhesive function and connect the plasma membrane to intermediate filaments in the cytoplasm.
- the connections are especially important in stratified epithelium as it helps form an internal tension-reducing networks of fibers.
gap junction
- consist of intercellular channels in the plasma membrane of adjacent cells.
- Small molecules can diffuse across the channel and into the cytoplasm of the other cell.
- “communicating junction” allows passage.
cell size is what size and what determines it?
- normally 5-20 micrometers
* limited by reliance on diffusion
definition of epithelium
Tissue that covers or lines surfaces and cavities of the body
or
(2) forms glands/ secretory structures
general characteristics of epithelium (7)
- Cellularity:
- Make specialized contacts
- Display polarity - apical, basal (e.g. goblet cell - secretes mucus)
- Basement membrane (anchors epithelium to the underlying connective tissue)
- Ability to regenerate quickly
- Avascular = no blood vessels • Innervated
functions of epithelium
• Absorption and Secretion (active transport)
-microvilla and cilia
• Diffusion and Filtration (passive transport)
• Sliding
• Protection
• Sensory reception

how do we classify epithelium?
by layering: simple vs stratified
by shape: squamous, cuboidal, columnar.
definition of a gland
structure whose cells are specialized for secretion
exocrine
type of gland that secretes products onto body body surfaces or into body cavities,
- contains ducts that carry these protiens to the surface (except the single celled goblet cells)
endocrine
glands that secretes hormones into the blood.
properties of reticular fibers
1] composed of type III collagen secreted by reticular cells.
[2] Reticular fibers crosslink to form a fine meshwork (reticulin). This network acts as a supporting mesh in soft tissues such as
-liver,
-bone marrow,
-tissues and organs of the lymphatic system.
-used at boundaries of tissues.
[3] Forms delicate networks with lots of spaces • Allows smooth gliding / deformation
areolar connective tissue
most widespread, ‘generic’, gel like matrix, lots of fluid, ADJOINS ALL EPITHELIAL, is a loose connective tissue
goblet cell
unicellular exocrine gland that is shaped as a goblet, secrets mucin that dissolves when secreated to form mucus
basal lamina
thin noncellular sheet that consists of proteins secreted by epithelial cells.
basement membrane
consists of the basal lamina and reticular fibers of the underlying connective tissue.
microvilla
almost every moist epithelia. but most abundant in small intestine (absorbs nutrients) and transport ions (kidneys).
cillia
- whiplike centoles projection from the apical surface of certain epithelial cells
- wavelike movement moves mucous (or reproductive cells) over the area in one direction only.
four main classes of connective tissue
connective tissue proper ( fat tissues, fiberous tissues et), cartilage, bone tissue, blood.
all connective tissues share the same structural plan.
- few cells, lots of extracellular matrix
- matrix composed of ground substance and fibers (elastic, collagen, reticular)
- all originate from the embrionic tissue, mesenchyme.
types of fibers found in the extracellular matrix
collagen- resists tension (bundles of thinner fibrils)
reticular- meshlike specialty collegen fibrils, covers and supports stuctures boardering the connective tissue. glide freely and provide more ‘give’ than collagen fibers.
elastic- stretch and recoil,
ground substance
the other component of the extracellular matrix.
-produced by cell type (fibroblasts, chondroblasts, osteoblasts)
two subclasses of connective tissue proper
loose connective tissue (areolar, adipose and reticular)
dense connective tissue (dense regular, dense irregular and elastic)
areolar connective tissue
gellike matrix with all three fiber types
cells: fibroblasts, macrophages, mast cells, some white blood cells
function: wraps and cushions organs, roll in inflamtion and immunity based on cell types, holds and conveys tissue fluid.
Location: widely distributed under epithelia of the body, surrounds organs, capillaries, forms lamina propria.
adipose connective tissue
loose connective tissue proper
matrix as in areolar but very sparse
closely packed fat cells,
function: provides reserve food fuel, insulates against heat loss, supports and protects organs
location: under the skin hypodermic, around kidneys and eyeballs, within abdomen, in breasts.
reticular connective tissue
loose connective tissue proper, loose ground substance, fibers lie on the network
function: stroma (soft internal skeleton) that supports other cell types including white blood cells, mast cells and macrophages.
location: lymphoid organs (bone marrow, spleen, lymph nodes)
types of cartilage
hyaline, elastic, fibrocartilage
hyaline cartilage
- amorphorous but firm matrix
- collagen fibers form the matrix
- mature chondrocytes lie in the lacunae
function: supports and reinforces, resilient cushioning properties, resists compression
location: - forms most of the embryonic skeleton, covers the ends of long bones,
- forms costal cartilage on the ribs, nose, trachea and larynx
elastic cartilage
similar to hyline cartilage but more elastic fibers in matrix.
function: maintains shape while allowing flexibility
Location: external ear and epiglottis.
fibrocartilage
matrix similar to hyaline but thick collegen fibers predominate.
function: tensile strength woth the ability to absorb shock.
location: intervertebral disks, pubic symphasis, discs of the knee joint.
dorsal body cavity
divided into two cavities, cranial (brain) and vertebral (spinal cord)
ventral body cavity
the organs it contains are called visceral/visera. divided into two cavities:
Thoratic and abdominopelvic , these are divided by the diaphragm.
cutaneous membrane
skin, outer epithelium is the thick epidermis and the inner connective tissue is the dense dermis.
mucous membrane or mucosa
- lines the inside of every hollow internal organ that is continuous to the outside world (respiratory, digestive, urinary and reproductive.)
- produces mucous and enzymes by secretion.
serous membrane
- lines the closed pericardial, pleural and peritoneal cavities.
- is the mesothelium ( simple squamous epithelium)
What are the differences between reticular cells, tissues (ct), reticular fibers and the dermis layer?
Cells- are fibroblasts within the ret. ct. Lie along the network of this tissue
CT- resembles areolar ct but the fibers are reticular fibers, fine and form a basic skeleton like the framework of a house. Create many caverns that hold free cells ( located in bone marrow, spleen and lymph nodes)
Fibers- they are bundles of a special collagen fibril. That cluster into a mesh like structures that are like fuzzy nets over capillaries and form part of the basement membrane for epithelium. These individual fibers glide easily and provide more give than other collagen fibers.
Dermis- contains interlacing fibers of elastic and collagen fibers that run on different planes. Ret. here means network and does not denote special forms of ‘reticular fibers.
Special characteristics of epithelium
- basal lamina
- cell junctions
- cilia and microvilla
