Chapter 4- Tissues Flashcards
Tissues
any grouping of cells that are similar in structure and carry out a similar or common function in the body.
Benefits of tissues
cellular specialization allows the body to carry out complicated functions
Drawback of tissues
destruction of one cell type could be catastrophic. A disease could enter the body to target the cells of one tissue. If a tissue is destroyed, there’s not much you can do
What are the 4 primary types of tissues?
- Nervous tissue- control tissue
- Muscle tissue- movement tissue
- Epithelial tissue- covering tissue
- Connective tissue- support tissue
Muscle tissue
Movement tissue- innervated, well vascularized
What must occur for muscle contraction?
Microfilaments actin and myosin allow for muscle contraction/movement- they do this by physically interacting with each other- this must occur for contraction
What are the 2 types of muscle tissue?
- Skeletal
- Cardiac
- Smooth
Skeletal muscle
voluntary control with striations. Attaches to bones and uses the bones to produce movement. A single muscle cell has multiple nuclei.
Skeletal muscle uses the bones like levers to move
cardiac muscle
involuntary control with striations, found only in the walls of the heart
Uninucleate- one nucleus per cell
Smooth muscle
involuntary control without striations. Found in the walls of hollow organs (not including the heart) to squeeze substances through the organ.
Also uninucleate
Epithelial tissue
The type of tissue that covers body surfaces, lines cavities, and forms glands
Epithelial tissue functions (2)
- Boundary forming, separates one area/region of the body from another
- Substances received or given off by the body must pass through the epithelium
What are the 2 forms of epithelial tissue
- Covering epithelium
2. Glandular epithelium
Covering epithelium
outer layer of skin, dips into and lines the urogenital, digestive, and respiratory systems. Covers the wall/organs of closed body cavities
Glandular epithelium
makes up the glands of the body
Apical basal polarity
Epithelial tissue has 2 surfaces that differ in structure in function. The apical surface and the basal surface
Apical surface
the exposed side of epithelial tissue- faces the lumen or outside of the body. Most have microvilli, others have cilia. The skin you can see is the apical surface of the epithelial layer
Lumen
an empty space through which something travels
Microvilli function
used to increase surface area, like the epithelia lining the intestines and kidney tubules
Cilia function
create current to propel substances through open space, like those lining the trachea
Basal surface
attaches to connective tissue
Has attached basal lamina- filters what can/can’t enter the epithelial layer. Also acts as a scaffolding along which epithelial cells can migrate to repair a wound.
Basal lamina
The basal lamina is a noncellular and adhesive sheet attached to the basal surface of epithelial tissue that consists mostly of glycoproteins secreted by the epithelial cells and some collagen fibers. Filters what can and can’t enter the cell, is one of the layers in the basement membrane
How are epithelial cells held together?
Joined by tight junctions and desmosomes
Epithelial tissue forms sheets- prevents passage of material between cells, resists mechanical stress
Basement membrane
lies between epithelial layer and connective tissue
Functions- reinforces epithelial sheet to resist stretching/tearing, defines epithelial boundary. Reinforces the desmosomes to strengthen the attachment. It has 2 layers: the basal lamina and the reticular lamina.
Semipermeable to certain substances- this is necessary because nutrients must diffuse through to the epithelium
Reticular lamina
contains fibers that belong to connective tissue. Deep to the basal lamina
What is an important characteristic of
cancerous epithelial cells?
An important characteristic of cancerous epithelial cells is their failure to respect the basement membrane boundary, which they penetrate to invade the tissues underneath
Does the epithelium have blood vessels?
No, it is avascular. It receives nourishment by diffusion and disposes of waste the same way
Is the epithelium innervated?
Yes
Is the epithelium able to regenerate?
Yes, there is a high capacity for regeneration.
Epithelial layers are subject to high levels of abrasion and hostile conditions (internal and external). For example, the stomach has a low pH, so the epithelia is constantly being destroyed
What begins when the epithelium is damaged?
When epithelial tissue is damaged, cell reproduction begins. If dead cells are not replaced, you lose the function
How many parts does the name of epithelial tissue have?
Two parts, like a first and last name. Thickness comes first, then the shape of the cells
Simple epithelia
Refers to the thickness of the tissue- contains only 1 layer of cells. Usually seen where absorption, secretion, and filtration are desired and a thin barrier is necessary, especially in areas where quick diffusion is needed, like the alveoli. These cells usually have the same shape.
Stratified epithelia
Refers to the thickness of the tissue- contains 2+ layers of cells. Usually seen in areas subjected to high levels of abrasion/contact (chemical or mechanical stress) like the skin surface and the inside of the mouth. These cells can have different shapes and are therefore named according to the shape of the cells in their apical layer
Squamous epithelia
The cells are flattened/squashed, the nucleus is flattened as well
Cuboidal epithelia
The cells are cube shaped and the nucleus is spherical
Columnar epithelia
The cells are tall and column shaped, the nucleus is elongated and closer to the cell base
Why isn’t simple epithelia used for protection?
There’s only one layer of cells
Simple squamous epithelium
Resemble a tiled floor, thin and permeable- includes the mesothelium and endothelium
Simple squamous epithelium function
absorption, secretion, filtration- part of the filtration membrane in the kidneys that filters blood to make urine.
Found in the lungs- must bring in oxygen at a regular rate and dispose of CO2 quickly- a thin layer allows for quick diffusion.
Mesothelium
A type of simple squamous epithelium, epithelium of the serous membranes that cover the ventral body cavity and organs
Endothelium
A type of simple squamous epithelium, forms slick/slippery linings. Lymphatic vessels and cardiovascular system- promotes the flow of the circulating material. Capillaries consist exclusively of epithelium- thinness encourages efficient exchange of nutrients and wastes between the bloodstream and surrounding tissue cells
Simple cuboidal epithelium
Single layer of cells as tall as they are wide
Nuclei are spherical and stain darkly
Locations- kidney tubules, ovary surface, some small glands
Simple cuboidal epithelium function
secretion and absorption
Simple columnar epithelium
Single layer of tall, closely packed cells. Many have microvilli on the apical surface of absorptive cells and tubular glands made primarily of cells that secrete mucus containing intestinal juice. Some have cilia that help move substances or cells through an internal passageway
Simple columnar epithelium functions
absorption and secretion
Simple columnar epithelium locations
digestive tract, gallbladder, small bronchi, uterine tubes, parts of uterus
Pseudostratified columnar epithelium
“False” stratified cell nuclei lie at different levels- the nuclei are displaced so it looks like there are multiple layers of cells.
Only some cells stretch from the apical surface to the basal surface. “Short” cells give rise to “tall” cells (the cells are different sizes). Shorter cells attach to the basement membrane
If tall cells are killed off, the shorter cells will replace them to prevent a loss of function.
Pseudostratified columnar epithelium function
secretion and absorption. Many types are ciliated.
Pseudostratified columnar epithelium locations
respiratory tract (cilia propels sheets of dust trapping mucus away from the lungs), male ducts, ducts of large glands The respiratory tract has a ciliated version with mucus containing goblet cells
How does stratified epithelia regenerate?
regenerate from the bottom up, the cells closest to the basement membrane divide mitotically to replace cells being rubbed off on the top
Stratified squamous epithelia function?
Thick, forms a good protective barrier
Why are the apical cells in stratified squamous epithelia poorly nourished?
the epithelium depends on diffusion for nutrients so apical cells in thicker tissues might actually be dead
Where is stratified squamous epithelia found in general?
Forms the external surface of the skin and extends a short distance into every body opening that is directly continuous with the skin
Where is the stratified squamous epithelia keratinized?
The outer layer (epidermis) of the skin is keratinized (its surface cells contain the tough protective protein keratin). The other stratified squamous epithelia of the body are non keratinized.
Stratified cuboidal epithelia
rare, usually consists of just 2 layers
Locations- mostly ducts of sweat glands and mammary glands, has 2 layers of cuboidal cells. Layers are mostly too thick to function
Stratified columnar epithelia
also rare, only apical cells are columnar
Locations- male urethra, part of pharynx, some ducts. Occurs at transition areas or junctions between two layers of epithelia
Transitional epithelium
Basal cells are mostly cuboidal/columnar, apical cell shape varies.
Typical of urinary organs- constantly being stretched- allows for greater flow of urine to flow through a tubelike organ
As the organs are stretched, the cells will look squamous in appearance
Cells will change shape as bladder fills/empties
Glands
one or more cells that produce and secrete a particular product (called a secretion)
Secretion
an aqueous fluid that contains proteins. Manufactured from the blood supply. Secretion is an active process- glandular cells obtain needed substances from the blood and transform them chemically into a product that is then discharged from the cell
What makes secretions different from each other?
The type of protein found in them makes one different from another
How are glands classified?
- Location of release- endocrine vs exocrine
2. Number of cells that makes up gland- unicellular vs multicellular
Endocrine glands
ductless glands. They release their secretion directly into the bloodstream (internally). They are not epithelial in nature and are multicellular. They produce hormones that are released to extracellular space via exocytosis
What types of organs/systems can endocrine glands form?
Can form
- Compact multicellular organs (cells are clumped together into a common structure) or
- Diffuse endocrine systems (the cells making up a gland are spread out).
Hormones
chemical messengers- target specific organs to respond in a specific way. They will go from the extracellular space to the blood or lymphatic fluid and travel to specific target organs.
Exocrine glands
secrete products onto surfaces/into cavities (externally secreting). Epithelial in nature, have a duct- a tube that empties the secretion onto a surface or into a body cavity- not into the bloodstream. Can be unicellular or multicellular.
Unicellular exocrine glands
release product onto surface via exocytosis. Individual cells that are scattered through epithelia with cells of different functions
Tend to be embedded in surrounding epithelial tissue
Example- goblet cells (digestive system), mucous cells (respiratory system)
Both produce and secrete mucin- dissolves in water to create mucus
Multicellular exocrine glands
release product onto surface via a duct- more structurally complex. Multicellular epithelial glands form by invagination (inward growth) of an epithelial sheet into the underlying connective tissue. These glands can be classified by structure (simple or compund) and mode of secretion.
Exocrine gland examples (5)
liver, pancreas (endocrine and exocrine), salivary glands, sweat glands, oil glands
What are the 2 parts of the multicellular exocrine gland?
- Duct- derived from epithelium. It’s just a passageway
2. Acinus- secretory unit made up of cells that produce and secrete product
How are multicellular exocrine glands classified based on structure?
- Simple- unbranched duct- one straight tube into secretory unit (acinus) or
- Compound- branched duct(s)
How are multicellular exocrine glands classified based on mode of secretion?
- Merocrine
- Holocrine
- Apocrine
Merocrine secretion
product secreted from the acinus via exocytosis, cell remains unchanged
Example- sweat or salivary glands
Holocrine secretion
product released as a result of cell rupture
Product builds up in the cell until the plasma membrane can’t hold it and it bursts
The cells that rupture are quickly replaced
Example- sebaceous glands
Apocrine secretion
similar to holocrine, but do not truly rupture
The cells have a small tear in the membrane so the secretion can leave, and the membrane quickly reassembles
Mammary glands could be an example
How is the secretory unit (acinus) of an exocrine gland characterized?
- Tubular- duct and acinus are the same width
- Alveolar- acinus is wider than the duct
- Tubuloalveolar- too tubular to be classified as alveolar and vice versa
What type of tissue is most abundant and widespread?
Connective tissue
Characteristics of connective tissue (3)
- Possession of extracellular matrix (ECM)
- Origin- all connective tissue arises from mesenchyme
- Vascularization varies widely between the different types of connective tissue
extracellular matrix (ECM)
nonliving matrix that separates living cells of the tissue. The living cells are widely separated and the ECM makes up most of the tissue.
Importance of the extracellular matrix in connective tissue
Because of its matrix, connective tissue can bear weight, withstand great tension, and endure trauma and abrasion
The extracellular matrix is made up of (2)
Made up by ground substance and fibers
Mesenchyme
The embryonic tissue that all connective tissue arises from. This tissue will eventually differentiate into all other connective tissue cells. Some cells will remain and provide a source of new cells in mature connective tissues.
Why does the skin have a large amount of connective tissue?
The skin has a huge amount of connective tissue so it can stretch and be supportive
Why doesn’t the nervous system have a lot of connective tissue?
Connective tissue is not conductive and could interfere with the conduction of electrical impulses.
What are the 4 classes of connective tissue?
- Connective tissue proper
- Cartilage
- Bone
- Blood
What are the major functions of connective tissue? (5)
- Support
- Protection
- Insulation
- Storage
- Transport
What are the 3 main structural components of connective tissue?
- Ground substance
- Fibers
- Living cells
Ground substance
viscous liquid that fills space between cells, contains fibers. Made up of 3 different components
What are the 3 components of ground substance?
- Interstitial fluid
- Cell adhesion proteins- “glue” that hold living cells to ECM
- Proteoglycans
Interstitial fluid
allows dissolved substances (like nutrients) to diffuse between the blood capillaries and the cells. The fibers in the ground substance make it less pliable and hinder diffusion somewhat. Found in ground substance
Proteoglycans
Consists of protein core with polysaccharide attachment
Gives ground substance its consistency, more proteoglycans= more viscous ground substance
What are the 3 types of fibers found in connective tissue?
- Collagen fibers
- Elastic fibers
- Reticular fibers
Collagen fibers
Contain the protein collagen. Assemble and cross link with other collagen fibers spontaneously, and are able to resist pulling forces. Strong, flexible- collagen fibers are stronger than steel fibers of the same size
Elastic fibers
Long and thin, form branching networks. Contains protein elastin- easily stretched, can return to normal shape
Where are elastic fibers typically found?
High density in areas of the body that are subjected to frequent stretching- skin, lungs
Reticular fibers
Continuous with collagen fibers- shorter and finer than other fibers and extensively branched to form fine networks
Where are reticular fibers typically found?
High density in areas of the body where connective tissue attaches to another tissue (basement membrane of epithelial tissues and around capillaries- allows more stretch than the other collagen fibers).
What are the 2 categories of cells that can be found in connective tissue?
- -blast cells
2. -cyte cells
blast cells
are actively mitotic, lay down ground substance/fibers
cyte cells
Mature cells that maintain what is/was laid down by -blast cells. Will signal blast cells if not enough ground substance. They can revert to their more active -blast form if the matrix is injured
Fibroblast/fibrocyte
Cells associated with the connective tissue proper
Chondroblast/chondrocyte
Cells associated with the cartilage
Osteoblast/osteocyte
Cells associated with bone
Adipocytes
Associated with adipose (fat) tissue
Macrophages
engulf foreign material in a variety of body tissues
Mast cells
oval cells that cluster along blood vessels and detect foreign microorganisms and initiate local inflammatory responses against them.
Mast cell cytoplasm contains secretory granules with chemicals that mediate inflammation, especially in severe allergies.
What types of chemicals are contained in mast cell cytoplasm? (3)
- Heparin
- Histamine
- Proteases- protein degrading enzymes
Histamine
a substance that makes capillaries leaky
Heparin
an anticoagulant chemical- prevents blood clotting when free in the bloodstream but regulates the action of other mast cell chemicals in mast cells
What contributes to a high amount of diversity between different types of connective tissue?
The composition and arrangement of the 3 components varies drastically- each connective tissue is adapted to perform a certain function in the body. All have a common structural plan, however.
Marfan syndrome
a genetic disorder that affects the body’s connective tissue- causes elastic fibers of connective tissue to lose flexibility and strength. Symptoms vary and may not appear until adulthood
What causes Marfan syndrome?
Results from a mutation in the FBN1 gene, which codes the production of fibrillin. This protein contributes to strength and elasticity
Individuals produce the wrong amount of fibrillin (usually not enough) or they won’t produce it at all.
Which organs/organ systems are typically most affected by Marfan syndrome?
- Bones/joints
- Heart/blood vessels
- Respiratory tract- loss of elasticity in the lungs
- Eyes
What type of bone/joint problems can a person with Marfan syndrome experience?
Bones and joints have fibers for strength and elasticity. Marfan syndrome may result in-
“Fighter fingers”- fingers and toes are especially long, but people tend to be very tall and lanky. Scoliosis is also common.
The sternum can be malformed- can sink in or project out
What types of cardiovascular problems can a person with Marfan syndrome experience?
blood is pumped out of the heart to the aorta, which stretches as blood passes through it. A person with Marfan syndrome will have an aorta that will lose elasticity and will be permanently stretched out
Results in inefficient blood flow, the walls of the aorta become thinner and will eventually split open if the walls become thin enough
What types of eye problems can a person with Marfan syndrome experience?
difficulty focusing vision- fibers holding the lens of the eye in place break/lose strength
Connective tissue proper
any connective tissue that is not bone, cartilage, or blood. Contains 2 broad types
What are the 2 broad types of connective tissue proper?
- Loose connective tissue
2. Dense connective tissue
3 types of loose connective tissue
- Areolar
- Adipose
- Reticular
Areolar connective tissue
most widely distributed, has a loose arrangement of fibers and a thick ground substance that can hinder movement of cells. Some WBCs can secrete an enzyme to liquify the ground substance and move through, but some pathogenic bacteria can do the same thing.
Areolar connective tissue is a universal packing material between other tissues- binds body parts together but allows them to move freely over one another.
It is also the connective tissue that most epithelia rest on and is present in all mucous membranes as the lamina propria
Areolar connective tissue functions
Functions- supports/binds other tissues (fibers), holds body fluids (ground substance), defends against infection (WBCs and macrophages), stores nutrients as fat in adipocytes (fat cells)
Areolar connective tissue chief cell type
Chief cell type is the fibroblast
Can also have adipocytes, macrophages, and mast cells
Adipose tissue
huge energy/nutrient source that will be used if the body is low on carbohydrates, composed mostly of adipocytes. Limited matrix. Adipose tissue is very important, too much removal of fat (through liposuction) can send the body into severe shock.
Where is adipose tissue usually found?
mostly subcutaneous (where it acts as a shock absorber, insulation, and energy storage site for the entire body), but can be found anywhere areolar tissue is found
What type of tissue has high metabolic activity
Adipose tissue. High metabolic activity- high turnover rate. Even if you maintain the same body fat percentage, the adipose tissue will change over time as its being used or replaced
Does the number of adipocytes in your body change?
No, when you lose weight, you’re just changing the amount of lipids deposited.
Reticular connective tissue
forms stroma (supportive network) to support free blood cells in lymph nodes, spleen, and bone marrow Good for supporting cells that are large in size
Adipose tissue function
it acts as a shock absorber, insulation, and energy storage site for the entire body- fat is a poor conductor of heat and therefore acts as an insulator
Where can fat accumulate in the body?
Fat can also accumulate around the kidneys, behind the eyeballs, and at genetically determined areas (abdomen and hips)
How do highly active organs meet their nutrient needs?
Smaller deposits of fat (not subcutaneous) serve the local nutrient needs of highly active organs. This can occur around the heart, lymph nodes, and in the muscles and bone marrow
3 types of dense connective tissue
- Regular
- Irregular
- Elastic
Dense regular connective tissue
There are a lot of fibers and a lot of fibroblast cells- limited matrix and ground substance. Collagen fibers run in the same direction and are packed together- that tension can only be applied in the same direction that the fibers are running. Tension pulling up or down makes it easy to cause damage.
Athletes that have to very suddenly move laterally will pull tendon fibers in the wrong direction, and ACL can break
Dense regular connective tissue usually forms (3)
Forms tendons (muscle to bone), aponeuroses (usually muscle to muscle, flat and sheetlike), and ligaments (bones to bones)
Dense irregular connective tissue
Collagen fibers are thicker than dense regular, there is an irregular arrangement of fibers with fibers are going in multiple directions
Can also withstand tension- tension can be applied in multiple directions
Where is dense irregular connective tissue usually found (2)?
Found in the dermis, joint capsules
Elastic connective tissue
Very elastic- tissue recoils easily after stretching
Found in parts of the body that stretch frequently- lungs, skin, large arteries
Cartilage (4)
Flexible, but still tough
Avascular, not innervated
Ground substance is very thick/firm, but it still contains large volumes of water
Will return to original shape if pressure is applied
3 types of cartilage
- Hyaline
- Elastic
- Fibrocartilage
Where is cartilage found?
Nose, external ear, precursor to bones in children
Hyaline cartilage
most abundant, individual cells are spread out. Firm yet pliable.
Elastic cartilage
Much more flexible than hyaline cartilage, found in areas requiring strength and exceptional stretchability - the external ear and epiglottis
Where is hyaline cartilage typically found? (5)
- Covers the ends of long bones as articular cartilage- provides springy pads that absorb compression at joints
- Supports the tip of the nose
- Connects the ribs to the sternum
- Supports most of the respiratory system passages (like the trachea, keeps them open)
- Makes up most of the embryonic skeleton before bone forms. Skeletal hyaline cartilage persists during childhood as the epiphyseal plates
Fibrocartilage
an intermediate between hyaline cartilage and dense regular connective tissues.
Rows of chondrocytes alternate with rows of thick collagen fibers
Where is fibrocartilage typically found?
found in areas of the body that need a lot of support/bear a lot of weight. Fibrocartilage discs are found between vertebrae
Why does cartilage heal very slowly?
Cartilage heals very slowly because it’s avascular and aging cartilage cells lose their ability to divide
Osseous tissue
Found in bone, highly vascularized- cells need oxygen and need to dispose of waste. Red bone marrow needs access to blood vessels so cells that it makes can enter.
What type of cells does osseous tissue contain?
Contains osteoblasts, osteocytes reside in the lacunae within the matrix
Bone salts deposited on/within fibers
What makes osseous tissue the hardest tissue in the body?
tissue contains inorganic calcium salts that make it rigid
Osseous tissue function
Support and protect body structures, provide cavities for storing fat and synthesizing blood cells
Why is blood considered a connective tissue?
it forms from the mesenchyme. Blood does not support/attach structures.
Where are blood fibers found?
Fibers form during blood clotting only- not usually found. Fiber formation must be very highly localized or blood flow and blood cell movement will be blocked.
What is the matrix of blood?
Plasma is the fluid matrix
What is the cellular portion of blood?
Blood cells- WBC, RBC, platelets. RBCs are the most common type
What is the function of blood
Does not provide support or physically connect one tissue to another
Function- transports nutrients, waste, gases, etc
What are the 3 types of covering and lining membranes?
- Cutaneous (skin)
- Mucous
- Serous
Cutaneous membrane
The skin, dry membrane. Composed of keratinized stratified squamous epithelia- keratin makes the skin dry, preventing infection as pathogens don’t like dry surfaces
Mucous membranes
Lines any body cavity that leads out of the body
Wet/moist membrane that has the function of absorption and secretion.
The epithelial cells of the mucous membrane are attached to
lamina propria (areolar connective tissue)
Serous membranes
Lines body cavities that are closed to the outside. Have visceral and parietal layers separated by serous fluid: visceral clings to organ, parietal clings to body cavity wall. Prevent organs from painfully rubbing against other things
Where are mucous membranes found?
Found in the hollow organs of the digestive, respiratory, and urogenital tract
Where are serous membranes found?
Can be pleurae (lungs), pericardium (heart), or peritoneum (abdominopelvic organs)
What are 3 protective barriers the body has?
- Skin and mucosa
- Cilia of the epithelial cells lining the respiratory tract
- Strong acid produced by the stomach glands
What happens when the protective barriers of the body are penetrated?
An inflammatory or immune response will occur. The injury must be closed off so nothing can get in and blood can’t leave
What are the 2 ways in which tissue repair can occur?
- Regeneration- occurs for small injuries. Surrounding healthy cells will divide and migrate to the area
- Fibrosis- scar tissue formation as well as clotting will occur for more severe injuries
Granulation tissue
The type of tissue that replaces a blood clot. Injured tissue looks bumpy/grainy and contributes to inflammation. Capillary growth in the injured area gives it a granular appearance
What are the 3 steps of tissue repair?
- Inflammation
- Organization restores blood supply (this mostly co-occurs with step 1)
- Regeneration and fibrosis effect permanent repair
What happens when inflammation occurs?
Inflammation occurs when blood vessels bleed and inflammatory chemicals are released.
Local blood vessels become more permeable and increase in diameter to increase blood flow and allow for WBCs, clotting proteins, and other substances to flood the area.
Clotting occurs, the surface dries and forms a scab
What occurs when organization restores blood supply?
The clot is replaced with granulation tissue, which restores blood flow under the scab surface (if a scab is ripped off too early, it will bleed as new capillaries are being ripped open)
Fibroblasts produce collagen fibers that bridge the gap of the injury- the collagen fibers are pulled to close the injury
Macrophages phagocytize dead and dying cells and other debris
Surface epithelial cells multiply and migrate over the granulation tissue
What occurs when regeneration and fibrosis cause permanent tissue repair?
The fibrosed area matures and contracts, the epithelium thickens
A fully regenerated epithelium with an underlying area of scar tissue results
Why would a scarred area of skin be discolored?
scar tissue has a different structure and will not be replacing the actual epithelium, so the color is different.
Neoplasm
A mass of cells that is caused by unregulated division of cells. Can be benign or malignant (very metabolically active).
What are the most common forms of cancer (4)?
Lung, skin, prostate, breast
What is the primary cause of cancer
The primary cause of cancer is mutation in DNA that alters the expression of multiple genes
This can be caused by a lot of things (smoking, toxins, UV radiation, prolonged infection, certain traumas)
Tumor suppressor genes
Normal genes that slow down cell division, p53 is an example
Oncogenes
A gene that is a mutated (changed) form of a gene involved in normal cell growth. Oncogenes may cause the growth of cancer cells
Proto-oncogenes
A gene involved in normal cell growth. Mutations (changes) in a proto-oncogene may cause it to become an oncogene, which can cause the growth of cancer cells.
Sarcoma
cancer arising in mesenchyme derived tissues (connective tissues and muscle)
Adenoma
any neoplasm of glandular epithelium, begin or malignant. A malignant type would be called an adenocarcinoma
What is the basement membrane made up of?
Fibers (like collagen), not cells
