Introduction and Tissues

• means "structure" 
• the physical aspects of something
• ex: the heart has 4 chambers (tells you what its like physically)

• means "function"
• what it does, how it works
• ex: the heart function is to pump blood

• it is well suited for its function
• ex: the heart is very muscular making it efficient for contracting. The left side has more muscle to pump the body while the right has less just for the lungs

walking- you need skeletal, muscular and nervous system: nervous system sends signals to muscles which pull on joints

chemical level → cell level → tissues → organs → organ systems → organismal level

• also known as molecular level
• atoms combine to form molecules (atoms and molecules combine to form cells)

smallest unit of living things

• the study of cells
• cyte means cells

• a group of similar cells plus the intercellular material between them. 
• all of the cells in this group have a common function
• ex: nervous tissue sends impulses

study of tissues

• a structure made up of at least 2 different types of tissue (usually its 4 types)
• they have a complex function
• ex: heart: blood (circulatory tissue) nervous tissue, membrane (epithelial tissue), muscle tissue

• groups of related organs with common complex functions
• ex: digestive system, endocrine system, etc

the organism, your whole body, made up of many organ systems

• Maintaining boundaries
• Movement
• Responsiveness or Excitability
• Digestion
• Excretion
• Reproduction
• Growth

• having a boundary is critical for survival for protection from bacteria and harmful things
• ex: skin on the surface of the body bs the external environment
• ex: internally- the cell membrane vx the internal environment of the body

• outside the cell fluid/material 
• also called intercellular

whats inside cells

• can be thought of in 2 ways
• a. of the whole body- walking, raising hand, etc
• b. within the body- stomach churning, blood flowing
• muscle cells have the ability of contracting for movement

most contraction involves shortening of a muscle or muscle cells

• the ability to sense changes in the environment and respond to them
• ex: something cold in the environment, light coming into your eyes, etc and you responding
• all cells can do this but it is one of the nervous cell's specialties

• break down of food to be absorbed into blood then used by cells for nutrition
• when nutrients get to cells they are utilized by metabolism which is all chemical reactions in the body

• synthesis reactions
• ex: amino acids to protein

• breakdown reactions
• ex: breakdown of sugars

removal of wastes from the body, these wastes can be excess substances (ex: too much water), useless things, or harmful substances

both cell and body reproduction

• living structures grow in two ways
• --> an increase in cell number making cells through mitosis
• --> an increase in cell size

• Nutrients
• Oxygen (needed to metabolize)
• Normal body temp
• Normal atmospheric pressure

• maintaining a relative balance, keeping things more or less constant
• it is a condition that varies within a narrow range, it isnt always exactly one number

• temperature
• ph
• blood pressure
• heart rate
• electrolytes
• oxygen levels

• through adaptation, the ability to cope with changes in the environment
• ex: at high altitudes, there is less oxygen, the body will breathe faster to get more and make more red blood cells

• Nervous system: nervous impulses
• Endocrine System: hormones secreted into blood

Walter Cannon

• measurement: ex- your body must know how much calcium is in the blood to determine if it is too high or low
• healthy range: ability to determine healthy set point
• ability to compare level with set point

a factor that is regulated

• a sensor that measures the level
• some part of the body that detects a stimulus such as low blood glucose
• responds by sending an imput into the control center (blood pressure control center is medulla oblongatta which controls your heart rate)

nervous cells in the chest are sensitive to high blood pressure and will send signals

• determines the set point 
• analyzes the info it receives and determines the response
• regulates an efferent pathway to to an effector
• ex: if blood pressure is too low it will set a signal to speed up heart rate
• does all this to maintain homeostasis

structure that will regulate the response output

• also called feedback inhibition- homeostasis is achieved by this, when the level of something is too high over the set point, the body will shut off any more of that being made
• stops things such as blood pressure becoming too high
• a self limiting system

• uncommon, not homeostasis
• a self stimulating system, a little stimulates more and more and more and nothing shuts it off, it is usually stopped by something physical
• ex: blood clotting- when you get a cut platelets set factors that start a chain reaction for more and more to be made until bleeding stops to stop production

• when aging, the body is less efficient
• older people usually have a higher blood pressure
• there are some people at any age that cant maintain- ex- untreated diabetic
• imbalance causes a disease, failure to fix can result in death

visualizing the body in medicine

• x ray
• CT scan
• MRI
• ultrasound
• PET scan

important for visualizing bone, heart structures and dense structures such as a tumor but not soft tissue

computed tomography- refined X-rays

• Magnetic resonance imaging
• uses magnets not X-rays, good for seeing soft tissue
• distinguishes fatty vs watery tissue

• uses sound waves, not harmful to a fetus like xrays can be
• shows images and some structures can be detailed in soft tissues but not everything is seen well if surrounded by bone (ex-brain) or air filled (such as the lungs)

• positron emission tomography
• not a static picture but you can see metabolic processes and movement
• involves injection of radioisotopes

• Epithelium
• Connective
• Muscle
• Nervous

• epi- a covering
• this type is found in several locations, covers body and organs (ex: membranes in kidney or in skin)
• also lines body cavities and found in glands

• spaces in the body which are also called lumens
• inside mouth, there is epithelial tissue, the opening is the lumen

bind, support and protect structures in the body (ex: cartialage protecting joints so bones dont rub)

Contracts for movement

• critical b/c it transmits impulses from one part of the body to another (type of communication)
• also important for controlling all types of organs
• ex: impulse to a gland to secrete

• at fertilization you have union of sperm and egg to form fertilized egg also called zygote
• multiplies by mitosis to make a ball of cells which hollows and forms layers

• ectoderm: outer layer; makes some epethilium and nervous tissue
• mesoderm: middle layer; makes some epithelium, nervous and connective
• endoderm: inner layer; some epithelium, internal organs

• internal organs in the cavities of the body
• ex: brain, kidney
• as opposed ot skin on outside or muscle on bone surface

• a little intercellular material (looks like cells are touching)
• rapid cell division (ex: scrape skin mitosis will replace quickly
• the cells can be in one or multiple layers

• one layer
• for functions like diffusion/absorption (ex: gas exchange in lungs)

• for protection and other functions
• ex:in skin lining mouth layered cells so if some fall off there are more underneath to protect

• squamous: broad and flat
• cuboidal: cube like
• columnar: elongated (nucleus usually near bottom); sometimes have cilia

• membranous: a covering or lining (skin, membranes of organs
• glandular: organs that make and secrete some sort of substance are glands

• outer
• secrete directly at the surface of a tissue
• ex: mucous in mouth
• or secrete into a duct (tube)
• ex: sweat glands

• inside
• secrete hormones into the blood
• ex: thyroid hormones, hydrocortisone, testosterone, etc

• simple squamous: one layer of broad flat cells; lungs
• simple cuboidal: kidney
• simple columnar: stomach
• pseudostratefied columnar: fake multiple layers but really only one w/ cells squeezed together, can be ciliated
• stratefied squamous: skin & esophagus 
• stratefied cuboidal: less common
• stratefied columnar: less common
• transitional epethilium: cells dont all look the same, happens in the bladder

no

• simple: the duct is straight and not branched
• compound: duct branches

• tubular: the cells that secrete form a tube
• areolar: the cells the secrete form a sac

ex: simple areolar or simple tubular

• merocrine: (most common) secrete by exocytosis (type of active transport)
• halocrine: (very uncommon) secretes when cell ruptures; seen in sebaceous glands

inner membrane formed around secretion and outer membrane opens to release it

• more intercellular material than epithelium and its nature (liquid, gel, solid) is important for its function
• connects, protects for framework of body (bones made of this tissue)
• not orderly like epithelial (esp loose connective tissue), theres spaces between cells

• brown substance or matrix
• there are fibers int he matrix such as collagen (very strong), flexible elastic fibers, and reticular delicate fibers

• "blast"-forming 
• "fibro"-fiber 
• these cells make the fibers, also will see fat cells and defense cells such as neutrophils

• areolar: loose connective tissue
• adipose tissue: fat, many fat cells

• connective tissue proper
• cartialage
• bone
• blood

the study of cancer

process of cancer development

agent causing a mutation (a change in the DNA of the cell) which causes cancer

some do (15-20%)

a cancer causing gene

these either inactivate the carcinogen or in some way prevent the DNA causing excess multiplication of cells

• not a carcinogen, but increases the risk of developing cancer
• ex: a high saturated fat diet is a risk factor of colon cancer, doesnt cause it, but increases the risk

• decreases the risk of developing cancer
• ex: high fiber diet decreases risk of colon cancer

skin and its derivatives (appendages such as hair nails, glands, etc)

• protection
• body temp regulation
• cutaneous sensations
• metabolic functions
• can serve as a blood reservoir (storage)
• excretion

• chemical barrier
• physical barrier
• biological barrier

• some chemicals in the skin decrease the growth of or destroy bacteria (acids, defensins, and cathelicidens are natural antibiotics)
• melanin- protien pigment that to some extent protects our body from UV rays

• stratefied epithelium has many layers to protect  from microbes/harmful material
• protection from water loss or gain due to many cell layers-water proofing glycolipids
• keratin is a hard protien (skin, hair, nails) that accummulates in the superficial dead layers. hard substance protects
• water proofing glycolipids

• defense cells
• langerhans cells, macrophages, and dendritic extentions important in phagocytosis

• if the body is hot it will sweat through skin
• skin blood vessels dilate, widen and heat radiates into the environment, cooling the body
• if the body is cold, blood vessels contract to keep heat in
• fat in hypodermis- acts as insulation for the body preventing heat loss and regulating temp

• women
• also many infants dont have much

• sensory receptors (nervous cells( give us info on our environment by responding to a stimulus
• --->exterocepters, tactile receptors, pressure receptors, hair follicle receptors (sense hair movement), pain receptors

sense stimulus on outside of the body

• both light touch
• meissners corpuscles
• merkel discs

• deep in the skin (dermis)
• pacinian corpuscles- not a free nerve ending, has a capsule at the end

free nerve endings

beginning with vitamin D synthesis (vitamin d is a derivative of cholesterol and on exposure to sunlight its synthesis begins)

• storage
• ex: if you are stabbed the blood can be shunted or moved from the skin vessels to another part of the body where you might need it, you constrict the skin and dilate in critical organ blood vessels

sweat: water, salts and some nitrogen containing wastes (such as ammonia, urea and uric acid)

• outer layer- epidermis: stratefied squamous epithelium
• inner layer- dermis: connective tissue
• subcutaneous layer- hypodermis:layer of connective tissue and fat (adipose)

medical specialty of the skin and its disorders

• keratinocytes: (most common) make keratin, cells closest to the dermis are active in mitosis; as they move to the surface of the skin they fill with keratin
• superficial cells: dead
• melanocytes: make melanin which is stored via granules in melanosomes (deep in epidermis)
• defense cells: langerhans cells
• merkel discs: at the junction btween dermis and epidermis

• no
• no sensory receptors except merkel discs

• palms, soles of feet, fingertips
• 5 layers of epidermis
• no hair

• thinner layers
• only 4 visible layers of epidermis
• has hair

• stratum corneum: outermost layer with dead filled keratin cells that fall off
• stratum lucidum: clear cells (not seen in thin skin)
• stratum granulosum: contains pigment granules
• stratum spinosum: looks spiny
• stratum basale:closest to the dermis and active in mitosis

• papillary layer (bump): right under epidermis; contains areolar loose connective tissue
• reticular layer: most tissue below papillary; dense irregular connective tissue

• much thicker than epidermis
• blood vessels, sensory receptors, hair follicles, and glands

• nerve supply to the skin
• sensory and motor nerves pick up sensory info from the skin and will deliver motor info to the skin

• stimulate movement of the hair
• stimulate secretion of the glands

• mostly melanin
• genetics
• caratine
• hemaglobin from blood

• deep in epidermis;color of melanin can vary from yellowbrown to red brown to black
• everyone has same # of melanocytes but type and amount of melanin varies bc melanosomes vary
• ---> if melanosomes spread out skin looks darker; freckles/moles are concentrations of melanosomes

the sun UV rays causes a spread of melanosomes to protect the DNA from being mutated and they make more melanin

• yellow/orange pigment
• in epidermis and dermis
• can also come from orange food like carrots

depending on how light your skin is if there is in an increase in bloodflow a red pigment can be seen

• also called pili
• a slender filament of keratin (tougher than the keratin in skin)
• not living except at base
• found all over the body except for palms, soles, lips, parts of genetilia, reproductive organs and sides of fingers/toes

• protection
• root has live cells with DNA but all parts of the hair can be used for tests of other types (drugs, led, etc)

• where the hair develops
• located where epidermis grows into the dermis

• due to melanin
• grey hair- air pockets in the hair
• white blonde hair- no pigment

• varies between active periods and rest periods
• a person hair grows fastest from teens to the 40s

• vellus hair: fine in texture; children and women have a lot
• terminal hair: courser, can be longer (eyebrows, scalp); men at puberty, some womens parts at puberty

baldness

there is some natural thinning of women and men as they age but male pattern baldness is genetic and influenced by testosterone

• excessive hairyness in women
• not just genetic variation
• due to unusually high testosterone from adrenal glands or ovaries

• arrector pili muscle
• sebaceous glands

• controls hair movement
• ex: in response to coldness or emotions, getting goosebumps, the hair will move

• secrete sebum
• epethilial cells here are light colored due to oil

• oil
• contains fats protein salts
• keeps hair supple/flexible and skin moist
• some antibacterial function
• released into a duct that reaches the surface of the skin

blocked sebaceous gland duct

• enlarged gland with sebum accumulation
• can be oxidized and dry

• an infection- blocked duct and bacterial infection
• antibiotics can treat it

• seborrhea
• overactive sebaceous glands
• patches on skin
• overactiveness can cause problems other than seborrhea as well

• contain keratin (stronger), modified epithelium
• formed by stratum corneum

• light nail part at top of nail
• whitish

• general nail part
• looks pinkish because of blood underneath, end looks white bc no blood under

• protection
• help grab things if long enough

• sebaceous glands (only attached to hair)
• sweat glands
• ceruminous glands (specialized)

• (sudoriferous glands) secrete perspiration into a duct which empties out at the small opening called the sweat pore on skin surface
• look darker under microscope

• eccrine glands
• apocrine glands

• common
• very widely distributed in the body
• also called merocrine glands although they are just a type (not crucial for test but know)
• release by exocytosis
• found on palms, soles, forehead
• doesnt contain organic molecules, just salt water and nitrogen waste

• larger and associated with hair follicles (only found on hairy body parts- armpit pubic etc)
• contain organic molecules (such as sugar) and bacteria on the surface decompose the sugars and create an odorous substance (B.O.)
• also called odoriferous glands
• start at puberty

• excretion
• temperature regulation

• secrete cerumin, or ear wax
• modified sweat glands in the ear canal
• ear wax protects from physical damage of the ear and from water loss/gain

• aging
• skin cancer
• burns

• changes occur in skin-increase wrinkling (infolding of skin)
• collagen in dermis becomes stiffer and skin becomes less elastic
• layers become thinner
• hypodermis and skin has less fat
• decrease in sebum- skin dries and cracks
• these changes can come from over exposure to sunlight

• can be precipitated by excessive sun exposure
• UV radiation increases risk, esp if you burn

• basal cell carcinoma (least problematic, most common)
• squamous cell carcinoma (2nd most common, more serious than basal but curable)
• melanoma (least common, most problematic)

• cancer of the stratum basal (lowest epi layer)
• slow growing and seldom spreads 
• 99% cure success by removal

• all epithelial skin cells are squamous but this deals with keratinocytes and stratum spinosum
• grows more rapidly and can spread
• high cure rate if caught early by surgery/radiation

• cancer of melanocytes
• spreads easily
• dangerous bc its hard to treat with chemicals making it hard to cure
• 2% of skin cancer

• an irregular shape of a growth, border is uneven
• different colorations
• generally large

• 1st degree: only epidermis damaged, red, painful swelling, heals 2-3 days (most nonblister sunburns)
• 2nd degree: epidermis and upper dermis, blisters, heal 3-4 weeks if no infection
• 3rd degree: a full thickness burn, epidermis and full dermis damaged, grey, red or black color; treated with antibiotics, IV fluids (bc risk of fluid loss and infection) and sometimes skin grafts; nerve endings destroyed

• offer some protection against 1 and 2 degree burns
• clear-absorb rays
• opaque- more effective; ZnO, block and reflect rays

skin inflammation

• infection: microbe is involved
• inflammation: any factor not necessarily microbe will cause a response (can be chemical, physical, etc)

• blood will flow to area with defense cells
• increase in blood clotting factors/platelets incase theres injury
• redness, dilated blood vessels bringing more blood causing swelling
• ex causing this: bug bite, poison ivy

• 1. inflammation (brings defense cells and platelets, blood clot will form scab)
• 2. organization to restore blood supply to area
• 3. Regeneration and Fibrosis

you will develop capillaries (microscopic blood vessels between arteries and veins) to restore blood supply to the dermis

• regeneration: mitosis of the cells in the epidermis (epithelial cells); takes place under the scab which will fall off after its restored
• fibrosis: many fiber in dermis bc its connective tissue; fibrous connective tissue forms in dermis to form a scar

• when a fetus develops in pregnancy it must develop all the different tissues
• develops a lanugo coat (soft delicate hair) which will later be replaced by vellus hair

• cheesy whitish looking substance that comes from sebaceous glands, skin covered at birth
• developed during pregnancy as a layer of protection from the amniotic fluid, goes away after birth

thickens

• mens skin becomes thicker
• hair and hair oil change
• women form reproductive hormones