the tissue level of organization - mrs. lips -...
TRANSCRIPT
CHAPTER 4
Study of different tissues Abnormal cells and tissues can be compared
to normal tissues to identify disease, such as cancer
Being able to know and recognize normal tissues under the microscope is the first step
PRACTICE There are thousands of images, virtual labs and practice
quizzes online DON’T MEMORIZE Tissues from the same organ will look vastly different
RECOGNIZE PATTERNS Don’t get lost in the big picture, look for patterns in how
cells are organized FORM = FUNCTION Keep in mind the function of the tissue and the organ
Tissue= collection of cells and cell products that perform specific, limited functions
Histology = study of tissues 4 types of tissues
1. Epithelial – cover and protection
2. Connective - support
3. Muscle - movement
4. Neural – signaling and communication
READ ONLY!!!
Covers body surfaces, lines cavities and forms glands
Characteristics
Cells are tightly packed together
Free surface exposed to environment = APICAL SURFACE
Attached to underlying connective tissue (basement membrane)
Avascular (no blood supply) – nutrients must diffuse
Continually replaced at exposed surface
1. Protection from abrasion, dehydration, destruction 2. Regulate gas and nutrient exchange 3. Provide sensation 4. Secrete substances such as sweat, hormones, mucus and
enzymes
1. First name indicates number of layers Simple: one layer of cells Stratified: more than one layer of cells Pseudostratified: appears to be stratified but is not
2. Second name describes the shape of the cells Squamous: thin and flat Cuboidal: cube shaped Columnar: tall, slender rectangles
1. Simple Squamous ▪ Description: single layer of flat cells ▪ Functions: diffusion and filtration ▪ Location: alveoli of lungs, walls of capillaries
2. Simple Cuboidal ▪ Description: single layer of cube-shaped cells ▪ Functions: secretion and absorption ▪ Locations: glands
3. Simple columnar ▪ Description: single layer, tall cells, often microvilli ▪ Function: absorption ▪ Locations: Lining of the small intestine
4. Stratified Squamous ▪ Description: many layers of flat cells (look at the shape of the
cells at the apical surface) ▪ Functions: Protection from abrasion, pathogens, and chemicals ▪ Locations: skin, lining of mouth
5. Pseudostratified ciliated columnar ▪ Description: single layer of columnar cells but the position of
the nuclei make it appear as there are many layers; often ciliated ▪ Functions: removing dust and particles from airways ▪ Locations: lining of respiratory tract
6. Transitional ▪ Description: transitions from one shape to
the next; often has a scalloped apical edge ▪ Functions: specialized to become stretched ▪ Locations: bladder
Practice Identifying epithelial tissues
Pseudostratified
Practice Identifying epithelial tissues
Simple Squamous
Practice Identifying epithelial tissues
Simple Cuboidal
Practice Identifying epithelial tissues
Stratified Squamous
Practice Identifying epithelial tissues
TRANSITIONAL
Practice Identifying epithelial tissues
Simple Columnar
Most diverse tissue of the body Most abundant Not as dense as epithelial tissue Highly vascular
Composed of
1. Specialized cells
▪ Mast cells (prevent blood clots)
▪ Macrophages (phagocytic)
▪ Fibroblasts (produce the tissue)
2. Matrix (protein fibers)
▪ Collagen (thick)
▪ Elastin (thin)
3. Extracellular Components (fluid and protein)
A. Collagen fibers B. Fibroblasts C. Mast cells D. Macrophages E. Elastic fibers F. Blood vessel/cells G. Fat cells
1. Support and protection 2. Transportation of materials 3. Storage of energy reserves (fat) 4. Fights infection, repairs tissue
1. Connective Tissue Proper a) Loose Connective (areolar) b) Adipose (fat) c) Dense Connective (fibrous or collagenous)
2. Cartilage a) Hyaline b) Elastic c) Fibrocartilage
3. Other Tissues a) Bone b) Blood c) lymph
1. Loose Connective Tissue (Areolar Tissue)
Structure: structural components are loosely arranged
Functions: cushion, support, movement, defense against pathogens
Locations: between other tissues and organs, beneath skin, digestive, respiratory and urinary tracts, between muscles, around blood vessels, nerves and joints
1. Loose Connective Tissue (Areolar Tissue)
2. Adipose (FAT)
Structure: Fibroblasts enlarge and store fat, very little matrix
Functions: stores energy, insulates and protects organs
Locations: beneath the skin and around organs especially at sides, buttocks, breasts, around eyes and kidneys
2. Adipose Tissue
3. Dense Regular
Structure: collagen fibers are parallel and are tightly packed
Locations: Tendons (connect muscles to bone) and Ligaments (connect bones to bones)
3. Dense Regular
Gel-type matrix For shock absorption and protection No blood vessels Types of cartilage include
Hyaline cartilage
Elastic cartilage
Fibrocartilage
1. Hyaline Cartilage Most common
Rubbery matrix
Covers ends of bones and joints and respiratory passages
2. Elastic Cartilage
Elastic fibers in addition to collagen
More flexible and elastic
External ear
3. Fibrous Cartilage (fibrocartilage)
Very tough, large numerous collagen fibers
Provides strong support and handles heavy pressure
Intervertebral discs
Most rigid connective tissue Rigid due to mineral salts
- Collections of cells in a fluid matrix - Blood consists of
- Red blood cells – transport oxygen throughout the body
- White blood cells – important components of the immune system
- Platelets – cell fragments that function in blood clotting
- Plasma – the watery matrix
- Lymph is formed when interstitial fluid enters the lymphatic vessels - Eventually returns to the cardiovascular system
- Monitored for signs of injury or infection
Physical barriers Line internal spaces of organs and tubes that
open to the outside Line body cavities Different types of membranes
Mucous
Serous
Cutaneous
Synovial
Mucous = protection Line passages that have external connections
Lining of digestive, respiratory, urinary and reproductive tracts
Epithelial surfaces are moist to reduce friction and help absorption and excretion
Line cavities not open to outside Are thin but strong Have fluid to reduce friction Three serous membranes
Pleura – lungs
Peritoneum – abdomen
Pericardium - heart
Outer covering of body Skin Thick, waterproof and dry Stratified keratinized squamous epithelium
Line freely movable joint cavities Secrete synovial fluid into joint cavity –
provides lubrication Protects the end of bones Lacks a true epithelium
Specialized for contraction Produces all body movement Three types
1. Skeletal
2. Cardiac
3. Smooth
1. Skeletal Muscle
Voluntary
Striated
multinucleate
Connected to skeletal system
2. Cardiac Muscle
Involuntary
Striated
Short branched cells connected by intercalated discs
Found only in the heart
3. Smooth muscle
Involuntary
Non striated
short
Walls of hollow, contracting organs (blood vessels digestive, respiratory, urinary and reproductive tracts)
Specialized for conducting electrical impulses Rapidly senses internal or external environment Processes information and controls responses Concentrated in the central nervous system
Brain and spinal cord
Two kinds of neural cells
Neurons = nerve cells
Neuroglia = supporting cells
Tissues respond to injury to maintain homeostasis
Any type of injury affects several tissue types simultaneously and these tissues must respond in a coordinated response to restore homeostasis
Two related processes
1. Inflammation
2. regeneration
The tissue’s first response to injury Signs and symptoms of the inflammatory response
Swelling, redness, heat, pain
Can be triggered by
Trauma (physical injury) or infection
1. Mast cells release chemicals to dilate blood vessels, increasing blood flow to the injury
Red and warm to touch
Swelling
2. Sensory nerve ending produce sensation of pain
3. Increased circulation delivers nutrients and white blood cells
1. Fibroblasts produce dense network of collagen fibers (scar tissue)
2. Most successful in epithelia, connective tissues and smooth muscle
3. Least successful in neural tissue, cardiac muscle
Speed and efficiency of tissue repair decrease with age due to
Slower rate of energy consumption (metabolism)
Hormonal alterations
Reduced physical activity
Osteoporosis – age related reduction in bone density
