Download Life cycle of cell

Cells & Tissues
Tissue – group of cells working together to perform a specific
function
Histology – the study of tissues
4 groups of tissues:
1. epithelial
2. connective
3. muscle
4. nerve
Epithelial – found of the surfaces as covering (skin) or on inner
surfaces as lining (digestive tract); many types are capable of
secretion (sweat, saliva, digestive enzymes)
A. Epithelial cells are classified according to shape and
arrangement of cells
1. Shape
1.
2.
3.
2. Arrangement
1. simple –
2.
stratified –
3.
transitional –
B.
C.
1.
Simple Squamous – important in the exchange of
materials or for absorption; found in capillaries, alveoli
(air sacs)
Stratified squamous epithelium
2.
3.
D. Simple Columnar Epithelial
1.
2.
3.
4.
E.
Simple Cuboidal (glandular epithelium)
1. single layer of cube-shaped cells
2. function in secretory activity
3. glands; cluster or groups of secretory cells
a. exocrine – release secretions into ducts (ex.
Salivary glands)
b. endocrine – release secretions directly into
bloodstream (ex. Thyroid gland)
F.
Stratified Transition Epithelium
1.
2.
G. Pseudostratified epithelium (ciliated)
1.
2.
3.
4.
Connective – most abundant tissue type, most varied, common to
all is the presence of a matrix in addition to cells – matrix is a
structural network or solution of non-living intracellular material
(ex. Blood matrix is plasma, bone matrix is calcium salts)
A. Aereola (loose connective tissue) most widely
distributed connective tissue
1.
2.
3.
4.
B.
C.
D.
E.
F.
Adipose
1. cells are called adipocytes
2. matrix consists of tissue fluid and some
collagen fibers
3. function – storage of lipids/cushion for
organs
Fibrous Connective Tissue
1. consists mainly of parallel collagen fibers
2. strong but flexible
3. makes up tendons and ligaments
1. tendon – connects muscle to bone
2. ligament – connects bone to bone
4. relatively poor blood supply, slow to heal
Bone
1.
2.
3.
4.
Cartilage
1.
2.
3.
4. function – prevent friction, absorbs shock,
permits movement
5. no capillaries, gets nourishment through
diffusion from surrounding tissues
Blood
1. Matrix is blood plasma
2. plasma contains dissolved salts, nutrients,
and waste products
function of plasma – transportation of
material around the body
4. cells of blood
1. red blood cells carry oxygen
2. white blood cells destroy pathogens –
principle component of the immune
system
3. platelets – prevent blood loss through
clotting
Hemopoietic tissue
1.
3.
G.
2.
Muscle – specialized for contraction, when muscles contract they
shorten and bring about some type of movement
A. Skeletal Muscle (striated or voluntary muscle)
1.
2.
3.
4.
B. Smooth Muscle (visceral or involuntary)
1.
2.
3.
4.
C. Cardiac Muscle (myocardium)
1.
2.
3.
4.
5.
Nerve Tissue
1. cells are called neurons, supporting cells are
neuroglia
2. function – transmit electrochemical impulses
3. structure of neuron
a. cell body – contains nucleus
b. axon – carries impulses away from cell
body
c. dendrite – carries impulses toward cell
body
4. each neuron has several dendrites that branch in
different direction
5. impulses are transmitted from one neuron to another
at the synaptic cleft by chemical messengers called
neurotransmitters
6. make up brain, spinal cord, and nerves
7. function – sensation, movements, regulation of body
functions, organization of information for learning
and memory