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1) Group of similar cells with a common function. 2) Bond together for a specific function. 3) Identified by function rather than location. 4) Note what is similar rather than what is dissimilar.
The study of tissues.
Major Tissue Types
1) Epithelial 2) Connective 3) Muscular 4) Nervous 5) All have subparts
1) Cover “free” body surfaces. 2) Serve as a protective barrier. Why? 3) cells tightly packed 4) no direct blood supply 4) readily divide 5)Attached to underlying connective tissue by basement membrane.
What does it mean that Epithelial tissues are completely cellular?
It means that there are no holes nor gaps. Only cells forming a barrier. 3) Wall to wall shoulder to shoulder
How do tissues get its blood and oxygenation?
They get it from below in the basement membrane underneath epith tissue.
Why does the skin readily divide?
1) They must replace themselves because a lot of our free surfaces experience friction 2) Interacting with the environment
Is the outer layer of the skin alive or dead?
It is dead - Living tissue is about 10-15 layers deep
What is mitosis?
Mitosis is the process in which cells duplicate
How do we classify cells?
1) By number of layers 2) By shape
What are the two groups of subclasses of cell layers of epithelial tissues?
1) Simple 2) Stratified
What does simple mean?
A single layer of cells (lungs).
Why do we need single layers of cells in lungs?
For diffusion. We need a delicate membrane so gas can readily go through in the process of diffusion.
Why do we need multiple layers of cells?
For greater protection. We need a stronger barrier on the bottom of our feet.
What are the cell shapes that we classify cells into?
1) squamous 2) cuboidal 3) columnar
What are squamous cells?And where are they found?
Single layer of scale-like or flattened. In lung
What are cuboidal cells?
1) Thicker 2) Squarish
What are columnar cells like?
Two or three cells higher than the squamous.
Where are you going to find simple squamous epithelial tissue?
Found in lungs
What do squamous cells look like?
What do squamous cells look like from the side?
1) Flattened with nuclei 2) Darker outline is the basement membrane where connective tissues connect to the epithelial tissue and also where the blood supply is.
Simple cuboidal epithelial
1) a little thicker 2) cuboid shaped 3) common at sites where secretion is needed
Where is the basement membrane located in simple cuboidal epithelial cells?
Outside and it is usually considered the bottom.
What does it mean that epithelial cells are polar?
It means there is a top and a bottom (basic membrane). In the intestine the “top” faces the food.
Simple columnar epithelial
1) thicker 2) column shaped 3) located where protection is needed 4) also important for secretion and absorption 5) location: digestive tract
Simple columnar epithelial tissue details:
1) Bottom has the basement membrane 2) Apical apex means the top
Do the microvilli help with movement?
No! Underneath the basement membrane there is smooth muscle that allow food to move through
What do goblet cells do?
1) Filled with mucus 2) spill it out to allow food or fecal matter to move more efficiently 3) located in lungs/oral cavity/vaginal cavity/rectum
Pseudostratified columnar epithelial
1) appear to be stratified 2)all cells reach the basement membrane 3) have cilia 4) location: respiratory tract
Stratified squamous epithelial
1) very thick 2) protective barrier 3) may be keratinized 4) location: epidermis of skin/oral cavity/esophagus/vagina/anus 4) Resistant to friction/heat 5) reinforced with a protein called keratin to
How often will we see Stratified cuboidal & columnar?
Not very often
1) really only see it well in the bladder 2) irregular not organized very well 3) has to make a barrier and has all the same tendencies as other epithelial except it has the ability to stretch 4) Still maintaining an air tight and water tight barrier.
Epithelium take home
Makes water proof and air proof boundaries.
How many classifications of glands are there?
Which two glands are we required to know?
1) Endocrine 2) Exocrine Endocrine glands
Why are pancreas/testicular/major adrenal/kidney cancers tend to be so aggressive?
Because they tend to be close to the blood supply
1) Require ducts typically made out of simple cuboidal tissue 2) Tube will lead somewhere else
What is the most abundant tissue by weight?
What is the most important thing to know about Connective Tissues?
It has a cellular and a non-cellular component.
1) Typically the non-living material 2) Called the extra (outside of) cellular matrix (ECM) What is the ECM? 1) Non-living matter including fibers made out of protein called ground substance
Blood is a connective tissue
red blood cells and white blood cells flowing in a liquid a plasma which is the ECM
Bone is a connective tissue
1) the non-living substance that makes up bone ECM is hard 2) bone cells are just as hard as blood cells 3) the hard stuff is the non-living stuff. How close are connective tissue cells?
non-living components of cartilage will have proteoglycans in it-just a molecule
What does blasts mean?
Refers to building or secreting something 2) Example osteoblasts make bone
Where are fibroblasts located?
Fibroblasts are in all connective tissue
What do fibroblasts make?
Fibroblasts make fiber typically collegen (tougher typbes of protein) and scar tissue
1) macro = large 2) phage = to eat
1) Secrete a chemical called histamine
What does histamine do?
1) Stops allergic responses 2) important when tissues get damaged like with a bee sting 3) tells the white blood cells that it needs blood
What happens if you get too many mast cells?
you get filled up with too much histomine and you could get anaphalactic shock
What do macrophages do?
Phagocytosis = cell eating
Connective Tissue fibers
1) Primarily collagen fibers (fibroblasts) 2) Great tensile strength!
Where are collagen fibers found?
application...: scar tissue
Protein Elastin fibers
1) Stretch fiber 2) adds elasticity to the tissue 3) behind nose and ears
much thicker than elastin fibers
1) Thinner 2) spread out throughout the tissue so you can stretch in any way.
Categories of Connective Tissues
1) Loose 2) Dense 3) Specialized
Loose (Irregular) Connective Tissues
1) Two types are areolar and fat (adipose) tissue 2) irregular loose 3) spread out and messy.
Dense (Regular) Connective Tissues
1) spread out tightly
mature bone cell
Bone cells (slide 31)
1) Inside the small holes are osteocytes
How do bones grow?
1) Concentric circle around osteon
What is a lacuna?
Little pit 2) Cavity or depression especially in a bone
Does bone tissue heal well?
Bone cells (osteocytes) with ECM of calcium phosphate salts and collagen fibers.
What are the three types of Cartilage Tissue? 1) Hyaline 2) Elastic 3) Fibrocartilage Cartilage Tissue
Chondrocytes in ECM
1) Bone is similar to cartilage
What are bones made out of?
Cartilege and then it becomes bone. What is softer? Cartilage or Bone?
1) costal cartilage of the ribs and knuckles 2) clear white-ish fluid 3) in joints to make sure they move
ears and nose
1) In the disks in the spine 2) between disks of the spine 3) are made out of fc 4) still has the jelly like stuff 5) Has a ton of cartilage reinforcing it making it much tougher
It can’t be bone because the women’s pelvis needs to open.
What is Blood Tissue composed of?
1) RBC’s - carry O2 2) WBC’s - fight infection 3) Platelets - blood clotting
1) look like jelly donuts 2) bend around capillaries 3) No nucleus at all 4) only last 3 months
have a large nucleus
involved in forming clots
Why are clots bad?
Clots restrict blood flow 2) Deep vein thrombis will flow until it stops. 3) Tissue death due to lack of oxygen.
Types of epithelial membranes
1) Membrane - sheet of cells 2) Serous - watery fluid - line cavities that do not open to the outside. 3) Mucous - secrete mucus - line cavities that do open to the outside. Why? 4) Cutaneous – skin 5) Note: CT Synovial membrane - lines a joint cavity
Types of cavities
1) membranes around heart/nose/etc. 2) Form a water and air-tight barrier
Mucous for getting exposed to outside air
some for our ability to smell or taste. What does mucous do?
SYNOVIAL synovial fluid.
1) Has dissolved oxygen 2) when you change the pressure you hear the pop 3) makes gas come out of liquid form and make bubbles 4) If you force a joint the wrong way
Why crack knuckles?
Most places we have cartilage there is oxygen inside the liquid. The joints of the knuckles move better after we crack them because it gets a better oxygen supply.
What are the three types of muscle tissue?
1) skeletal 2) smooth 3) cardiac
Muscle tissue can contract
1) Attach to bones and moves joints 2) We can move by thinking about it 3) VOLUNTARY.
1) Within visceral organs and blood vessels 2) arteries 3) visceral organs 4) inside arteries 5) intestines Which muscles change the blood flow?
1) Contracts all by itself. 2) The heart is by definition Unfatiguable
Cardiac muscle visualized (slide 37)
1) Branched cardiac muscle 2) cells have to be able to wrap around in a “round organ.” The heart is not a piece of steak. 3) Electrical conduction. 4) Striated/striped has ridges(important in how muscles contract.)
Smooth muscle visualized (slide 37)
Smooth muscle has no stripes
Skeletal muscle visualized (slide 37)
Skeletal muscle is striped/striated for contraction purpose.
1) Transmits information via electrical impulses
What are the nerve cells called and what supports them?
1) Nerve cell is called a neuron 2) Neuroglial cells support neurons.
Where are neurons located?
1) Brain 2) Spinal cord 3) Peripheral nerves
What are the peripheral nerves?
Peripheral nerve are the nerves that leave the spinal cord and go to the 1) extremities 2) rest of the viscera and into the body
What are the two major parts of the nervous system?
Central NS and Peripheral NS They operate entirely differently.
Brain and Spinal cord
All the other nerves outside the brain and spinal cord
What is one thing that is different from the central nervous system and the peripheral nervous system?
1) Severed nerves in the CNS don’t grow back 2) Severed nerves in the PNS do grow back about a mm a day
What happens if you cut a nerve in your spinal cord?
It will never grow back. If you cut a nerve in your spinal cord that is connected to your diaphragm you will not be able to breath and you will die. Cannot inhale because nerve for contraction of diaphragm is severed. You can do things to reprogram you brain but the cells inside your brain will never grow back
Even though we talk about electrical pathways in the NS which is how the signal is brought. the muscles also respond to electrical stimulus. So a muscle can contract using an electrical signal. But muscles also use electrical signals to depolarize just as the nervous system does. What does this mean? Tissue engineering - A patient’s cells and ECM are grown on a synthetic scaffold. Give an example:
1) Bladder: a patient’s progenitor cells are grown in a fluid “cocktail” of growth factors 2) then placed on the scaffold 3) then implanted back into the patient. 4) Later the scaffold degenerates.