Chapter 4: Tissue: the Living Fabric Flashcards
Tissues: definition
Groups of cells that work together to perform a specific function
4 types of tissues
- Epithelial
- Connective
- Muscle
- Nerve
Epithelial Tissue
- Composed almost entirely of cells
- Form continuous sheets held together by tight junctions and desmosomes
- Supported by connective tissue - reticular and basal laminae (basement membrane).
- Avascular but innervated - contains no blood vessels but supplied by nerve fibers
- Regenerative - rapidly replaces lost cells by cell division
The basement membrane is like
double sided sticky tape
How permeable is epithelial tissue to water? why?
Waterproof like a pool liner. It’s a continuous sheet. There are no spaced between the cells which makes it waterproof.
Which layer of skin is the oldest?
The surface. The deepest layers of skin are the newest.
Naming tissues - 1st name is based on…
number of layers. Simple, stratified
Tissues that are classified as simple are used for
filtering and diffusion
Tissues that are classified as stratified are
places that shed. surface of skin, mouth, etc
Naming tissues - last name is based on…
shape. squamous (squatty), cuboidal (cube-like), columnar (column-like).
Epithelia: Simple Squamous - Structure
Single layer of flattened cells with disc-shaped nuclei and sparse cytoplasm
Epithelia: Simple Squamous - Functions
- Diffusion and filtration.
2. Provide a slick, friction-reducing lining in lymphatic and cardiovascular systems.
Epithelia: Simple Squamous - Locations
Present in the kidney glomeruli, lining of heart, blood vessels, lymphatic vessels, and serosae
Epithelia: Simple Cuboidal - Structure
Single layer of cube-like cells with large, spherical central nuclei.
Epithelia: Simple Cuboidal - Function
secretion and absorption
Epithelia: Simple Cuboidal - Location
Present in kidney tubules, ducts and secretory portions of small glands, and ovary surface.
Epithelia: Simple Columnar - Structure
Single layer of tall cells with oval nuclei; many contain cilia. Goblet cells are often found in this layer
Epithelia: Simple Columnar - Function
absorption and secretion
Epithelia: Simple Columnar - Location
1, Nonciliated type line digestive tract and gallbladder.
2, Ciliated type line small bronchi, uterine tubes, and some regions of the uterus
What to cilia do?
they help move substances through internal passageways
Epithelia: Pseudostratified Columnar - Structure
Single layer of cells with different heights; some do not reach the free surface. Nuclei are seen at different layers
Epithelia: Pseudostratified Columnar - Function
secretion and propulsion of mucus
Epithelia: Pseudostratified Columnar - Location
Present in the male sperm-carrying ducts (nonciliated) and trachea (ciliated)
Epithelia: Stratified Squamous - Structure
Thick membrane composed of several layers of flat-cells
Epithelia: Stratified Squamous - Function
protection of underlying areas subjected to abrasion
Epithelia: Stratified Squamous - Location
Forms the external part of the skin’s epidermis (keratinized cells),
and linings of the esophagus, mouth, and vagina (nonkeratinized cells).
Epithelia: Stratified Cuboidal - Structure
Typically two, cubed shaped cell layers thick
Epithelia: Stratified Cuboidal - Function
? Rare
Epithelia: Stratified Cuboidal - Location
some sweat and mammary glands
Epithelia: Stratified Columnar - how often
limited distribution in the body
Epithelia: Stratified Columnar - Location
Found in the pharynx, male urethra, and lining some glandular ducts. Also occurs at transition areas between two other types of epithelia
Epithelia: Transitional - Structure
Several cell layers, basal cells are cuboidal, surface cells are dome shaped
Epithelia: Transitional - Function
Stretches to permit the distension of the urinary bladder.
Epithelia: Transitional - Location
Lines the urinary bladder, ureters, and part of the urethra
What is a gland?
a gland is one or more cells that makes and secretes an aqueous fluid
How are glands classified?
- Site of product release – endocrine or exocrine.
2. Relative number of cells forming the gland – unicellular or multicellular
Glandular tissue falls under what group of tissue?
Epithelia
What are endocrine glands?
ductless glands that produce hormons
what do endocrine glands produce?
secretions include amino acids, proteins, glycoproteins, and steroids
Which are more numerous - exocrine or endocrine glands?
exocrine glands
where do exocrine glands secrete?
onto body surfaces (skin) or into body cavities
examples of exocrine gland secretions
mucous, sweat, oil, salivary glands
what is the only important unicellular exocrine gland?
goblet cell
Multicellular exocrine glands are composed of…
a duct and secretory unit
Multicellular exocrine glands are classified according to
- Simple or compound duct type.
2. Structure of their secretory units
Where is connective tissue found?
throughout the body. it is the most abundant and widely distributed in primary tissues
Types of connective tissue
- Connective tissue proper (loose or areolar).
- Cartilage
- Bone
- Blood
Functions of connective tissue
- Binding and support
- Protection
- Insulation
- Transportation
Characteristics of Connective tissue - Connective tissues have…
- Mesenchyme as their common tissue of origin.
- Varying degrees of vascularity.
- Nonliving extracellular matrix, consisting of ground substance and fibers .
What is the extracellular matrix made of?
ground substance and fibers
What embryonic layer does connective tissue arise from?
mesenchyme
What are the structural elements of connective tissue?
- Ground substance
- Fibers
- Cells
Connective Tissue - ground substance - what is it
unstructured material that fills the space between cells
What fibers are there in connective tissue?
collagen, elastic, reticular
What cells are in connective tissue?
fibroblasts, chondroblasts, osteoblasts, and hematopoietic stem cells
White blood cells, plasma cells, macrophages, and mast cells
What makes up ground substance?
- Interstitial (tissue) fluid.
- Adhesion proteins – fibronectin and laminin
- Proteoglycans – glycosaminoglycans (GAGs)
- Functions as a molecular sieve through which nutrients diffuse between blood capillaries and cells
What is the function of ground substance?
Functions as a molecular sieve through which nutrients diffuse between blood capillaries and cells
Describe a collagen fiber
tough, provides high tensile strength
Describe an elastic fiber
long, thin fibers that allow for stretch
Describe a reticular fiber
branched collagenous fibers that form delicate networks
How can you tell the difference between epithelial cells and connective tissue cells by appearance?
Epithelial - looks like houses
Connective - don’t look similar to each other. Classification is based on function, not on what it looks like
Which cells are more tightly linked, epithelial or connective?
epithelial
What does connective tissue have on the outside?
an epithelial layer
How many types of connective tissue fibers are there?
3
when can you see blood fibers?
only when blood is clotting. they stay stretched out until clotting starts, then they clump up
What are the adhesion proteins?
fibronectin and laminin
What is the protoeoglycan in ground substance?
glycosaminoglycans (GAGs)
What do GAGs do? - glycosaminoglyans
make a sieve to filter things in connective tissue
Where are fibroblasts?
connective tissue proper
Where are chondroblasts?
cartilage
Where are osteoblasts?
bone
Where are hematopoietic stem cells?
blood
What is mesenchyme?
embryonic connective tissue
What is mesenchyme made of?
gel-like ground substance with fibers and star-shaped mesenchymal cells
What does mesenchyme give rise to?
all other connective tissues
where is mesenchyme found?
in the embryo
Connective Tissue Proper: Loose: Areolar - Structure
Gel-like matrix with all three connective tissue fibers.Fibroblasts, macrophages, mast cells, and some white blood cells
Connective Tissue Proper: Loose: Areolar - Function
wraps and cushions organs
Connective Tissue Proper: Loose: Areolar - Location
Widely distributed throughout the body.
Connective Tissue Proper: Loose: Adipose - Structure
Matrix similar to areolar connective tissue with closely packed adipocytes
Connective Tissue Proper: Loose: Adipose - Function
- Reserves food stores,
- insulates against heat loss, and
- supports and protects
Connective Tissue Proper: Loose: Adipose - Location
Found under skin, around kidneys, within abdomen, and in breasts. Local fat deposits serve nutrient needs of highly active organs
Connective Tissue Proper: Loose: Reticular - Structure
Loose ground substance with reticular fibers. Reticular cells lie in a fiber network
Connective Tissue Proper: Loose: Reticular - Function
Forms a soft internal skeleton, or stroma, that supports other cell types
Connective Tissue Proper: Loose: Reticular - Location
Found in lymph nodes, bone marrow, and the spleen
Connective Tissue Proper: Dense Regular: Structure
Parallel collagen fibers with a few elastic fibers. Major cell type is fibroblasts
Connective Tissue Proper: Dense Regular: Function
Attaches muscles to bone or to other muscles, and bone to bone
Connective Tissue Proper: Dense Regular: Location
Found in tendons, ligaments, and aponeuroses
Connective Tissue Proper: Dense Irregular: Structure
Irregularly arranged collagen fibers with some elastic fibers. Major cell type is fibroblasts.
Connective Tissue Proper: Dense Irregular: Function
Withstands tension in many directions providing structural strength
Connective Tissue Proper: Dense Irregular: Location
Found in the dermis, submucosa of the digestive tract, and fibrous organ capsules
Connective Tissue: Hyaline Cartilage - Structure
Amorphous, firm matrix with imperceptible network of collagen fibers. Chondrocytes lie in lacunae
Connective Tissue: Hyaline Cartilage - Function
Supports, reinforces, cushions, and resists compression
Connective Tissue: Hyaline Cartilage - Location
Forms the costal cartilage. Found in embryonic skeleton, the end of long bones, nose, trachea, and larynx
Connective Tissue: Elastic Cartilage - Structure
Similar to hyaline cartilage but with more elastic fibers
Connective Tissue: Elastic Cartilage - Function
Maintains shape and structure while allowing flexibility
Connective Tissue: Elastic Cartilage - Location
Supports external ear (pinna) and the epiglottis.
Connective Tissue: Fibrocartilage Cartilage - Structure
Matrix similar to hyaline cartilage but less firm with thick collagen fibers
Connective Tissue: Fibrocartilage Cartilage - Function
Provides tensile strength and absorbs compression shock
Connective Tissue: Fibrocartilage Cartilage - Location
Found in intervertebral discs, the pubic symphysis, and in discs of the knee joint
Connective Tissue: Bone (Osseous Tissue) - Structure
Hard, calcified matrix with collagen fibers found in bone. Osteocytes are found in lacunae and are well vascularized
Connective Tissue: Bone (Osseous Tissue) - Function
Supports, protects, and provides levers for muscular action. Stores calcium, minerals, and fat. Marrow inside bones is the site of hematopoiesis.
Connective Tissue: Bone (Osseous Tissue) - Location
Bones of Skeleton
Connective Tissue: Blood - Structure
Red and white cells in a fluid matrix (plasma)
Connective Tissue: Blood - Function
Transport of respiratory gases, nutrients, and wastes
Connective Tissue: Blood - Location
Contained within blood vessels
How many types of cells are there in the nervous system? What are they?
2 - Neurons and Neuroglia
Neuroglia -
support and protect neurons, do not send action potentials
Neurons -
do impulse or action potential conduction
Examples of Neuroglia
- Protoplasmic astrocyte
- Fibrous astrocyte
- Microglia
- Oligodendrocytes
Where are reticular fibers found?
in the lymphatic system. sed to filter lymph
Where are collagen fibers found?
in cartilage and calcified in bone
When is mesenchyme undifferentiated?
Day 1-12 of pregnancy
What happens on day 12 of pregnancy
mesenchyme forms primary layers
what do mesenchyme cells replicate from?
fertilized egg - copies. undifferentiated
Areolar connective tissue makes up
the basement membrane or lamina propria
fascia
what does areolar connective tissue do?
sticks every layer of tissue together
to store more fat, the adipose cells do this
stretch. they don’t multiply
in males, adipose tissue is more____ because of _____
yellow, testosterone
reticular connective tissue does what for other cells?
forms a framework, a soft internal skeleton (stroma) to support other cell types
Reticular connective tissue is like a
collander
Dense regular connective tissue looks like
waves. neat and parallel to each other (fibers), but not straight
which is stronger - dense regular or irregular?
irregular
Nervous Tissue: Structure
Branched neurons with long cellular processes and neuroglia or support cells
Nervous Tissue: Function
(neuron)Transmits electrical signals from sensory receptors to effectors
Nervous Tissue: Location
Found in the brain, spinal cord, and peripheral nerves
How do neuroglia compare in size and number to neurons?
smaller but outnumber neurons by 50 times
What is the purpose of neuroglia?
support cells for neurons
What are the types of neuroglia?
Astrocytes Oligodendrocytes Microglia Ependymal Cells Schwann Cells Satellite Cells
What are gliomas?
tumors - make up 1/2 of brain tumors - highly malignant - grow quickly
Neuron Structure
- *3 parts**
1. Cell Body
2. Dendrites
3. Axon
Neuron Cell Body
Central to neuron cell, contains typical organelles of cell. (Found in clusters in the CNS called nuclei, outside the CNS clusters are called ganglia.)
Dendrite
Dendrites: Cytoplasmic processes
- Short, branched extensions of cell body cytoplasm
- Many
- Receive impulses and bring them to cell body.
- Axon hillock: point where axon attaches to cell body.
What is the axon hillock?
point where axon attaches to cell body
Axon
Axon: Cytoplasmic process
1 long extension from cell body.
Sends impulses to another neuron, gland or muscle.
End of an axon—synaptic bulb/axon terminals—stores neurotransmitter-signal to next neuron to continue or stop an impulse. Forms synapse/junction with next neuron or effector cells. Neurotransmitter travels from presynaptic neuron to postsynaptic neuron via synaptic cleft.
May branch into collaterals
What does an axon do?
sense impulses to another neuron, gland, or muscle
What does a dendrite do?
receives impulses and brings them to cell body
what is the end of an axon?
synaptic bulb/axon terminal
what does the axon terminal do?
stores neurotransmitter-signal to next neuron to continue or stop an impulse
forms synapse/junction with next neuron or effector cells
the neurotransmitter travels from _____ to ______ via _____
presynaptic neuron, postsynaptic neuron, synaptic cleft
Muscle Tissue: Skeletal - Structure
Long, cylindrical, multinucleate cells with obvious striations
Muscle Tissue: Skeletal - Function
Initiates and controls voluntary movement.
Muscle Tissue: Skeletal - Location
Found in skeletal muscles that attach to bones or skin
Muscle Tissue: Cardiac - Structure
Branching, striated, uninucleate cells interlocking at intercalated discs
Muscle Tissue: Cardiac - Function
Propels blood into the circulation
Muscle Tissue: Cardiac - Location
Found in the walls of the heart
Muscle Tissue: Smooth - Structure
Sheets of spindle-shaped cells with central nuclei that have no striations.
Muscle Tissue: Smooth - Function
Propels substances along internal passageways (i.e., peristalsis).
Muscle Tissue: Smooth - Location
Found in the walls of hollow organs
Tissue trauma cases
inflammation
inflammation is characterized by
- dilation of blood vessels
- increase in vessel permeability
- redness, heat, swelling, and pain
Epithelial Membranes: Cutaneous Membrane
Cutaneous - skin
Epithelial Membranes: Mucous Membrane
Mucous – lines body cavities open to the exterior (e.g., digestive and respiratory tracts)
Epithelial Membranes: Serous Membrane - what are they
Serous – moist membranes found in closed ventral body cavity
Name the serous membranes
Parietal peritoneum - gut Visceral peritoneum - gut Parietal pleura - lungs Visceral pleura - lungs Parietal pericardium - heart Visceral pericardium - heart
Parietal (serous membranes)
not against organ - more superficial
Visceral (serous membranes)
against organ
Tissue Repair steps
- Organization and restored blood supply
- Regeneration and fibrosis
- Fibrous tissue matures and begins to resemble the adjacent tissue
- Results in a fully regenerated epithelium with underlying scar tissue
Tissue Repair - Organization and restored blood supply - the blood clot is replaced with…
granulation tissue
Tissue Repair - Regeneration and fibrosis - what happens when the surface epithelium regenerates?
the scab detaches
What are the primary germ layers?
3 layers of cells formed early in embryonic development
- ectoderm
- mesoderm
- endoderm
The primary germ layers specialize to
form the four primary tissues
Nerve tissue arises from
ectoderm
Muscle, connective tissue, endothelium, and mesothelium arise from
mesoderm
most mucosae arse from
endoderm
epithelial tissues arise from
all three germ layers
ectoderm becomes
nerve tissue
mesoderm becomes
Muscle,
connective tissue,
endothelium, and
mesothelium
endoderm becomes
mucosae
What are fontanels made of?
Hyaline cartilage
Why doesn’t cartilage heal well?
because it’s avascular
What does avascular mean?
without blood supply
Which connective tissue has the most collagen?
fibrocartilage
What makes the matrix of osseos tissue hard?
calcium
How does bone get nutrients?
It is vascularized. The central canal is a blood vessel. The little striations radiating out from the center are tiny blood supplies. They are little canals through the bone.
Which blood cells are nucleated?
White blood cells
which blood cells are not nucleated?
red blood cells, plasma
Where is cardiac muscle found?
ONLY in the heart
what kind of muscle is found in the blood vessels?
smooth muscle
what is the function of intercalated discs?
to synchronize the contraction of cardiac muscle fibers so that the muscle pumps as a whole unit
what layers are all of the “tubes” of the body comprised of?
epithelial
connective
smooth