AnP Chapter 5 (LO4) Flashcards
tissues
Group of similar cells that perform a common function
entire body including blood and bone is made of tissue
4 distinct groups of tissue
epithelial
connective
nervous
muscular
functions of tissue
tissue holds together the body
provides the body with it’s shape
gives it the ability to move
TISSUE DEVELOPMENT
- once egg/sperm unite to form a single cell it begins to divide rapidly (all identical)
- cells organize into 3 layers
- ectoderm (outer layer)
- mesoderm (middle layer)
- endoderm (inner layer) - Cells continue to divide; each layer becoming distinct from other layer
- Differentiation: each layer gives rise to different type of tissue
Ectoderm
outer layer
gives rise to epidermis and nervous system
- epidermis
- nervous tissue
Endoderm
inner layer
produces mucous membrane of respiratory tract, thyroid gland, secretory parts of pancreas
- Lung tissue
- thyroid tissue
- pancreatic tisssue
mesoderm
middle layer
gives rise to connective and muscle tissue
- cardiac muscle
- skeletal muscle
- bone
- blood
Stem cells
differentiate into many different types of cells such as liver cells, skin cells or blood cells
200 types
EPITHELIAL TISSUE
surface tissue
Continuous sheet of tightly packed cells
Covers body surface, lines body cavities/organs and forms certain glands
It’s top surface usually exposed to the environment
It’s bottom surface adheres to underlying connective tissue (basement membrane)
Too thin to contain blood vessels; depends on the connective tissue underneath to supply it oxygen and nutrients
key functions of epithelial tissue
Protection
Absorption
Filtration
Secretion
Join with tight junctions and make it difficult for some substances to pass between cells
CLASSIFICATION OF EPITHELIAL TISSUE
Classified by shape of the cells and # of layers
cell shapes
squamous
cuboidal
columnar
cell layers
simple epithelia
-Every cell touches the basement membrane
Stratified epithelia
-Some stack on top of others and upper layers of cells don’t touch basement membranes
Glandular epithelium
- exocrine glands
- endocrine glands
- goblet cells
Gland
a collection of epithelial cells that specializes in secretion of a particular substance
Exocrine glands
secrete their products (sweat, tears, gastric juices) into ducts
The ducts empty onto a body surface inside a body cavity
Endocrine glands
ductless glands; secrete products (hormones) into the blood
ex) adrenal glands secrete epinephrine and norepinephrine into blood includes: pituitary, thyroid, ovaries
Goblet cells
modified cells containing secretory vesicles that produce large quantities of mucus
definition, function and locations: Simple squamous epithelium
- consists of a single layer of flat, scale like cells
- allows for ready diffusion or filtration because of thinness
- Alveoli
- lining of blood and lymphatic vessels
definition, function and locations: Simple cuboidal epithelium
- consists of a single layer of cube like cells
- secretes and absorbs
- ducts and tubules of many organs including kidneys
definition, function and locations: Simple columnar cells
-consists of a single layer of columnar cell
- participates in absorption
- secretes mucus by goblet cells
-lines intestines
definition, function and locations: Pseudostratified columnar
Pseudostratified columnar
- consists of a single layer of irregularly shaped columnar cells
- cells of different heights with nuclei at different levels makes it appear stratified
- protection
- secretes mucous
-lines trachea large bronchi and nasal mucosa
stratified definition
several layers
definition, function and locations: stratified squamous epithelium
- contains multiple cell layers (making it stronger than simple epithelia)
- most wide spread epithelium in the body
- resist abrasions and penetration by pathogens
- some contain keratin (such as the epidermis) some do not (such as the mucous membrane)
- epidermis of skin
- esophagus
- vagina
definition, function and locations: Transitional epithelium
- consists of multiple layers
- when stretched, cell layers decrease and cell shape changes from cuboidal to squamous
- stretches to allow filling of urinary tract
- urinary tract
connective tissue
Most widespread and most varied
Connects together and binds, supports and protects organs
TYPES OF CONNECTIVE TISSUE
Dense fibrous (ligaments) Adipose (fat) Bone Blood Areolar (under epithelial) Reticular (frame work of spleen) Cartilage (vertebral discs)
COMPONENTS OF CONNETIVE TISSUE
Extracellular matrix
Framework into which the cells of tissues are embedded
Consists of varying kinds/amounts of protein fibers and fluid (variation in composition that gives tissues it’s characteristics)
May be: gel-like, flexible, tough, fragile, brittle or liquid
Extracellular matrix
allows connective tissues to be diverse
3 TYPES OF FIBERS FOUND IN CONNECTIVE TISSUE
Collagenous fibers
Reticular fibers
elastic fibers
how are connective tissues classified
according to their structural characteristics
classifications of connective tissue
loose or dense
- areolar tissue
- adipose tissue
- reticular tissue
Cartilage
Bone
Blood
FIBROUS CONNECTIVE TISSUE
Fibers may be loosely arranged or tightly packed
DENSE CONNECTIVE TISSUE
Consists of closely packed collagen fibers
tendons
ligaments
tendons
cord-like structures attaching muscle to bone
Ligaments
cord like structures attaching bone to bone
loose connective tissue
Most widely distributed of all tissues
Stretchable quality
Areolar, adipose, reticular
AREOLAR TISSUE
-consists of collagen and elastin fibers in a soft, gel like matrix
- connects many adjacent structures in the body
- lies underneath almost all epithelial
-surrounds blood vessels, nerves, the esophagus and trachea
ADIPOSE TISSUE
- dominated by fat cells
- forms supporting, protective pads around the kidneys and various other structures
- acts as a storage depot for excess food
- helps insulate the body to conserve body heat
RETICULAR TISSUE
- consists of a loose network of reticular fibers and cells
- forms the frame work of the spleen, lymph nodes and bone marrow
CARTILAGE
Composed of cells called chondrocytes
Rubbery, flexible matrix
No blood vessels; receives nutrients and 02 by diffusion from surrounding connective tissue
When cartilage is damaged it heals very slowly or not heal at all
3 types of cartilage
HYALINE CARTILAGE
FIBROCARTILAGE
ELASTIC CARTILAGE
Osteocytes
bone cells
Composed of osteocytes embedded in matrix containing collagen fibers and mineral salt crystals (responsible for hardness of bone)
Form the skeletal body
Gives structure, protects internal organs, offer attachment point for muscle making movement possible
Matrix of bone serves as a storage site for calcium and some bones contain red bone marrow which produces new blood cells
Has a rich blood supply allowing bone to heal quickly after a fracture
BLOOD
Exists as a fluid
Surrounded by plasma
Transports cells and dissolved substances from one part to another
Doesn’t contain any fibers
TYPE LOCATION FUNCTION OF CONNECTIVE FIBER: areolar
- beneath the epithelial
- between muscles
- surrounding blood vessels and nerves
-connects tissues and organs together (skin to muscle)
TYPE LOCATION FUNCTION OF CONNECTIVE FIBER: adipose
- beneath skin, breast, heat’s surface
- surrounding kidneys and eyes
- provides protective cushion
- insulation
- stores energy
TYPE LOCATION FUNCTION OF CONNECTIVE FIBER; reticular
- spleen
- lymph nodes
- bone marrow
-provides supportive framework
Hyaline
- ends of bones in joints
- connecting point between ribs/ sternum
- rings in trachea/bronchi
- larynx
- fetal skeleton
- eases joint movement
- firm but flexible support
elastic
external
-provides flexible support
Fibrocartilage
- intervertebral discs
- knee joint
- pelvis
-resists compression and absorbs shock
bone
-skeleton
- provides support, protection
- serves as calcium reservoir
blood
-inside blood vessels
- inside blood vessels
- transports oxygen, nutrients, hormones, waste from one part of body to nother
NERVOUS TISSUE
High degree of excitability and conductivity
Found in brain, spinal cord and nerves
Consists of 2 types of cells
Neurons
units that conduct nervous impulses
Neuroglia
which protect and assist neurons
Soma
large cell body; contains nucleus of nerve cell as well as organelles
Dendrites
short processes; receive impulses from other cells which transmit to soma
axon
single long nerve fiber; transmits signals to other cells
MUSCLE TISSUE
Consists of elongated cells that contract when stimulated
3 types of muscle tissue: skeletal, cardiac and smooth
Skeletal muscle
- muscle fibers: long, thin cells
- striated muscle
- Voluntary
- most is attached to bone
- makes body movement possible
- breathing, speech, urination, and facial expressions
Cardiac muscle
- striated but shorter than skeletal
- intercalated discs: cells joined together with junctions
- junctions allow electrical impulses to spread rapidly from cell to cell (contraction)
- only found in heart
- involuntary
Smooth muscle
- long, spindle-shaped cells
- not striated
- stimulated by autonomic nervous system
- Involuntary
- lines walls of many organs (digestive, respiratory and urinary tracts)
- controls blood pressure and flow
Regeneration
occurs when damaged tissue cells are replaced with the same type of cells resulting in functional new tissue
Most skin injuries heal by regeneration
Fibrosis
occurs when damaged tissue is replaced with scar tissue (mostly collagen
Binds the edges together but doesn’t restore normal function
Severe cuts or burns, muscle and nerve tissue heal through fibrosis
Muscle/nerve tissue have limited capacity to regenerate causing loss of partial function
STEPS IN TISSUE REPAIR
1.When cut occurs in skin, the severed blood vessels bleed into the wound
- Blood clot forms and forms scab
- Beneath scab are white blood cells that ingest bacteria/cellular debris - Healthy tissue surrounding the wound sends blood, nutrients, proteins and other materials necessary for growing new tissue to damaged area
Granulation tissue: newly formed tissue - Surface area wound generates new epithelial cells
These cells migrate beneath the scab
Scab loosens and falls off revealing new functional tissue
Necrosis
irreversible cell injury and death
Gangrene
refers to death of tissue due to inadequate blood supply
Dry Gangren
efers to death of tissue without any bacterial involvement
Wet gangrene
involves a bacterial infection and can be life-threatening
membranes
Thin sheets of tissue
Line body cavities, cover body surfaces and separate organs from each other
Some secrete lubricating fluids to reduce friction during movement
Categories of membranes
- epithelial membranes 2. connective tissue membranes
3 types of epithelial membrane
mucous, cutaneous and serous
Mucous membrane
Line body surfaces that open to body’s exterior (respiratory, digestive, urinary, reproductive)
Type of epithelium in each mucous membrane varies
Secrete mucous
Cutaneous membrane
Skin; body’s largest membrane
Consists of a layer of epithelium resting on a layer of connective tissue
serous
lines the wall of the cavity then folds back and covers organs
Composed of simple squamous epithelium resting on layer of areolar connective tissue
Serous membranes line some closed body cavities and cover many organs
Serous membrane is actually one continuous sheet
Parietal membrane
lines the wall of the cavity then folds back and covers organs
Visceral membrane:
is part that covers the organs
3 serous membranes
pleura
pericardium
peritoneum
Pleura
surrounds each lung and lines the thoracic cavity
Pericardium
surrounds heart
Peritoneum
lines abdominal cavity and covers the abdominal organs
ONNECTIVE TISSUE MEMBRANES
Some joints are lined by membranes made of connective tissue
Synovial membrane
