Chapter 5 Tissues
Tissues-a group of similar cells that performs a specialized function
4 types of tissues
1. Epithelial
2. Connective
3. Muscle
4. Nervous
5.2 Epithelial Tissue
- covering organs, forming inner linings of body cavities, and lining hollow organs
basement membrane-layer of non-living material that anchors epithelial tissue to underlying connective tissue
-lack blood vessels get nutrients from underlying connective tissue
-readily divide, heal rapidly
-tightly packed
Classified according to shape and number of layers of cells
1.
2.
3.
4.
5.
Simple- single layer of cells
Stratified-two or more layers of cells
Squamous-thin flattened cells
Cuboidal-cube-shaped cells
Columnar-elongated cells
1. Simple squamous epithelium- single layer of thin, flattened cells that are fit tightly together
-substance pass easily through
-line the air sacs of lungs
-forms walls of capillaries
-lines insides of blood and lymph vessels
-covers membranes that line body cavities
2. Simple cuboidal epithelium-single layer of cube-shaped cells
-cover the ovaries
-lines most of the kidney tubules
-lines the ducts of glands, such as salivary, thyroid, pancreas, and liver.
3.Simple Columnar Epithelium-single layer of elongated cells
-tissue is thick
-lines the uterus and most organs of the digestive tract
4 Pseudostratified Columnar
Epithelium-appear layered but are not
-commonly have cilia
-line the passages of the respiratory system
5. Stratified Squamous Epithelium- many cell layers make it relatively thick
-forms outer layer skin
-line the mouth, throat, vagina, and anal canal
6.
Stratified Cuboidal Epithelium-consists of two or three layers of cuboidal cells that form the lining of a
lumen
-line the ducts of the mammary glands, sweat glands, salivary glands, and pancreas.
-also forms the lining of developing ovarian follicles and seminiferous tubules
7. Stratified Columnar Epithelium-several layers of cells
-found in the male urethra and vas deferens and the pharynx
8. Transitional Epithelium-specialized to change in response to increased tension
-forms the inner lining of the urinary bladder and lines the uterus and part of urethra
9. Glandular Epithelium-composed of cells that are specialized to produce and secrete substances into ducts or into
body fluids
Exocrine glands-secretes its products into a duct or onto a body surface
3 types
1. Merocrine glands-secretes a fluid without losing cytoplasm
2.Apocrine glands-secretions contain parts of secretory cells
3. Holocrine glands-secretion contains entire secretory cells
Endocrine glands-secretes hormones directly into the blood or body fluids
5.3 Connective Tissues
-bind structures, provide support, serve as framework, fill spaces, store fat, produce blood cells, protect against
infections, and repair tissue damage
matrix-intercellular material of connective tissue
Major Cell types
1. Fibroblasts- produce fibers by secreting proteins into the matrix
- most common type of cells
2. Macrophages-specialized to carry on phagocytosis
-function as scavenger and defensive cells that clear foreign particles from tissues
3.
Mast cells-located near blood vessels
-release heparin, which prevents blood clotting
-release histamine, which promotes reactions associated with inflammation and allergies
Fibroblasts produce three types of connective tissue fibers
1. Collagenous fibers-flexible, slightly elastic, resist pulling force
-hold structures together, such as ligaments and tendons
2. Elastic fibers-common in body parts that are frequently stretched such as vocal cords
3. Reticular Fibers-highly branched and form delicate supporting networks in a variety of tissues
Categories of Connective Tissue
1. Connective Tissue Proper
a.
Loose-areolar
- binds the skin to the underlying organs and fills spaces between muscles
b.
-
Adipose tissue or fat- lies beneath the skin, in spaces between muscles, abdominal membranes, on the
surface of the heart, and around certain joints
cushions joints and some organs
insulates beneath the skin
stores energy in fat molecules
-
c.
Dense- has few cells, very strong enabling the tissue to withstand pulling forces
binds body parts together
in the protective white layer of the eyeball
in deeper skin layers
Specialized Connective Tissues
1. Cartilage-rigid connective tissue, provides support, framework, and attachments.
-protects underlying tissue and forms structural models for developing bones
chondrocytes-cartilage cells
3 types of cartilage
A. Hyaline-most common
-found on the end of bones in many joints
-soft part of nose
-supporting rings of the respiratory passages
B. Elastic-more flexible than hyaline
-provides framework for the external ears and for parts of the larynx
C. Fibrocartilage-shock absorber
-forms pads between individual bones of the spinal column
-cushions bones in the knee and in the pelvic girdle
2. Bone-most rigid connective tissue
-hardness is due to mineral salts between cells
-internally support body structures
-protects vital parts in the cranial and thoracic cavities
-attachment for muscles
-contains red marrow, forms blood cells
osteocytes-bone cells
3.Blood-transports materials between interior body cells and those that exchange substances with the external environment
-composed of formed elements suspended in a fluid matrix called blood plasma
Muscle Tissues:
-are contractile, can shorten
-as they contract, they pull at their attached ends, and this moves body parts
Three types
1. Skeletal Muscle Tissue- Found in muscles attached to bones
- Voluntary muscles-controlled by conscious effort
- Have striations, alternating light and dark cross-markings
- Move the head, trunk, and limbs
- Make facial expressions, write, talk, sing, chew, swallow, and breathe
2. Smooth Muscle TissueDoes not have striations
Tissue comprises the walls of hollow internal organs, such as stomach, intestine, urinary bladder, uterus, and
blood vessels
- They are involuntary
-
-
3. Cardiac Muscle TissueOnly in the heart
Makes up most of heart and pumps blood through heart chambers and into blood vessels
Controlled involuntary
Nervous Tissues- Found in the brain, spinal cord, and peripheral nerves
- Basic cell is called neurons (nerve cells)
- Transmit nerve impulses along cytoplasmic extention
-
Coordinate, regulate, and integrate many body functions