Chapter 3,4 And 5

50-100 Trillion cells

Differentiation is when cells specialize. Each cell has a specific function. As a result of differentiation cells vary in size and shape due to their unique function.

A composite cell is a sample of a cell that contains all the parts of a "typical" cell. There are 3 major parts: nucleus, cytoplasm and cell membrane.

Outer limit of the cell. It controls what moves in and out of the cell. It's selectively permeable. Cholesterol stabilizes the membrane. It has a phospholipid bilayer ( water-soluble heads form surfaces, water-insoluble tails form interior, permeable to lipid-soluble substances)

Receptors: bind with molecules (hormones) and trigger responses, part of the immune system.

Pores, channels and carriers: allow for flow of molecules into and out of the cell

Peripheral Membrane Proteins CAMS (cellular adhesion molecule like "post it notes")

Self-markers: distinguish one cell from another

Made of two basic parts: Cytosol = water

Organelles = solids

Cytoplasm is like a jello fruit salad where the jello is the cytosol and the fruits are the organelles.

Endoplasmic Reticulum (ER) connected, membrane-bound sacs, canals and vesicles.

Transport system, synthesize CHO, lipids and proteins, can act as storage.

There are 2 types: Rough ER (studded with ribosomes) and Smooth ER (break down of drugs)

Ribosomes: Free floating or connected to ER

plays an important role in the formation of proteins

Stack of flattened membranous sacs, modifies, packages, and delivers proteins

Membranous sacs and stores substances.

Membranous sacs with inner partitions - "Powerhouse" of the cell: Generates Energy

Enzyme containing sacs (called suicide sacs) that digest worn out cell parts or unwanted substances such as bacteria

Enzyme containing sacs that break down organic molecules

Two rod like centrioles, used to produce cilia and flagella, distributes chromosomes during cell division.

Short hair like projections that propel substances on cell surfaces

Long tail like projection. Provides motility to sperm

Thin rods of various sizes and tubules built around protein called tubulin. Supports cytoplasm and provides a framework in the cell. Determines consistency of cytoplasm.

Temporary nutrients and pigments are "floating" around in the cytoplasm

Contain an assortment of protein-digesting enzymes (proteases). Smaller than free ribosomes. Remove proteins from cytoplasm for recycling into amino acids and small peptides released into the cytoplasm.

Allows substances in and out of the nucleus. Porous double membrane. Seperates nucleoplasm from cytoplasm.

Dense collection of RNA and proteins. Site of ribosome production.

Fibers of DNA and proteins. Stores information for synthesis of proteins.

2 polynucleotide chains: repeating unit of phosphate and deoxyribose sugar. Bases pair form the "rungs" (A-T and C-G of a ladder). Adenine only bonds with Thymine. Cytosine only bonds with Guanine. Hydrogen bonds hold nitrogenous bases together. Froms a helix. DNA wrapped around histones, forms chromosomes.

Hydrogen bonds break between bases. Double strands unwind and pull apart. New nucleotides (in the cytoplasm) pair with exposed bases. Controlled by DNA polymerase.

Consists of the correct sequence of amino acids in polypeptide chain. Each amino acid is represented by a triplet code called a codon.

The formation of proteins are controlled by DNA with the use of RNA. The formation of proteins in the body is called protein synthesis. Protein synthesis takes place in the ribosomes of the cell.

3 types

Messenger RNA (mRNA): Making of mRNA (copying of DNA) is transcription

Transfer RNA (tRNA): Carries anticodon to mRNA with attached amino acids. Translates a codon of mRNA into an amino acid

Ribosomal RNA (rRNA): Provides structure and enzyme activity for ribosomes.

Delivers genetic information from nucleus to the cytoplasm and then to the ribosomes. Single polynucleotide chain. Formed beside a strand of DNA this process is called Transcription. RNA nucleotides are complementary to DNA nucleotides (exception - no Thymine in RNA; Thymine is replaced with Uracil)

In the ribosomes mRNA attaches to the rRNA located in the ribosome. Each three bases of mRNA represents a codon. tRNA contains three bases that "match up" with mRNA. These three bases are called anticodons. Attached to the tRNA for the most part are amino acids. Some anticodons are used as stop and start signals. This process is called Translation. Amino acids are attached to each other forming a protein.

Only about 1/10 of one percent of the human genome differs from person to person.

Mutations - change in genetic information.

There are several types of mutations. One type results when: extra bases are added or deleted. May or may not change the protein. Some mutations are point mutations-happen at just a point in the DNA. Some mutations are chromosomal mutations and happen to a part of or a whole chromosome. Ex: Down's Syndrome

Repair enzymes correct the mutations in most cases.

Passive (physical) processes: Require no cellular energy and include: simple diffusion, facilitated diffusion, osmosis and filtration.

Active (Physiological) Processes: require cellular energy and include: active transport, endocytosis,exocytosis and transcytosis.

Movement of substances from regions of higher concentration to regions of lower concentration.

Diffusion across a membrane with the help of a channel or carrier molecule. Substances that use facilitated diffusion to get into and out of the cells are glucose and amino acids.

Movement of water through a selectively permeable membrane from regions of higher concentration to regions of lower concentration.

The ability of osmosis to generate enough pressure to move a volume of water. Increases as the concentration of nonpermeable solutes increases (substances outside the cell)

Same osmotic pressure in and out of the cell. Equal amount of solutes in and out

Higher osmotic pressure (water loss) more solutes out of the cell than inside.

Lower osmotic pressure (water gain) less solutes out of the cell than inside.

Smaller molecules are forced (pushed) through porous membranes. Hydrostatic pressure important in the body. Molecules leaving blood capillaries

Carrier molecules transport substances across a membrane from regions of lower concentration to regions of higher concentration. Energy is required to do this.

Active transport mechanism. Creates balance by "pumping" three sodium (Na+) OUT and two potassium (K+) INTO the cell 3:2 ratio

Cell engulf's a substance by forming a vesicle around the substance. Three types:

Pinocytosis: Substance is mostly water

Phagocytosis: Substance of a solid

Receptor Mediated Endocytosis: Requires the substance to bind to a membrane bound receptor

Reverse of endocytosis. Substances in a vesicle fuse with a cell membrane. Contents released outside the cell. Release of nuerotransmitters from nerve cells.

Endocytosis followed by exocytosis. Transports a substance rapidly through a cell. HIV crossing a cell layer

Series of changes a cell undergoes from the time it forms until the time it divides. 3 Stages: Interphase, Mitosis, Cytokinesis.

Very active period. cell grows. cell maintains routine functions. Cell replicates genetic material to prepare for nuclear division. Cell synthesizes new organelles to prepare for cytoplasmic division.

Phases: G phases-cell grows and synthesizes structures other than DNA

S phase- cell replicates DNA

Produces two daughter cells from an original somatic cell. Nucleus divides-karyokinesis. Cytoplasm divides-cytokinesis. Phases of nuclear division:

Prophase: Chromosomes form; nuclear envelope disappears

Metaphase: Chromosomes align midway between centrioles

Anaphase: Chromosomes seperate and move to centrioles

Telophase: Chromatic forms;nuclear envelope forms

Cell division capacities vary greatly among cell types: Skin and blood cells divide often and continually. Neuron cells divide a specific number of times then cease.

Chromosome tips (telomeres) that shorten with each mitosis provide a mitotic clock. Cells divide to provide a more favorable surface area to volume relationship. Growth factors and hormones stimulate cell division: hormones stimulate mitosis of smooth muscle cells inuterus. Epidermal growth factor stimulated growth of new skin. Contact (density dependent) inhibition. Tumors are the consequence of a loss of cell cycle control.

Two types of tumors: Benign-usually remains localized. Malignant-invasive and can metastasize, cancerous. Two major types of genes cause cancer:

Oncogenes-activate other genes that increase cell division

Tumor supressor genes-normally regulate mitosis, if inactivaed they are unable to regulate mitosis-cells are now known as "immortal"

Stem cells: Can divide to form two new stem cells-self renewal-can divide to form a stem cell and a progenitor cell

Tolipotent: can give rise to every cell type

Pluripotent: Can give rise to a restricted number of cell types

Progenitor cell: Commited cell-can divide to become any of a restricted number of cells-pluripotent

Apoptosis- programmed cell death-acts as a protective mechanism-is a continuous process.

Tissues

The study of tissues

1) Epithelial tissue

2) Connective tissue

3) Muscle tissue

4) Nervous tissue

Close space between cells - Located among cells that form linings

Form "spot welds" between cells - Located among outer skin cells

Tubular channels between cells - Located in cardiac muscle cells

Covers organs and the body inside and out. Has a free surface. Has a basement membrane. Are avascular (no blood supply). cells readily divide. Cells tightly packed with one or more layers of cells. Cells often have desmosomes. Function in protection, secretion, absorption and excretion.

Single layer of flat cells. Substances pass easily through. Line air sacs. Line blood vessels. Line lymphatic vessles

Single layer of cube-shaped cells. Line kidney tubules. Cover ovaries. Line ducts of some glands.

Single layer of elongated cells. Nuclei usually near the basement. Sometimes possesses cilia and microvilli. Often have goblet cells. Line uterus, stomach and intestines.

Single layer of elongated cells. Nuclei at two or more levels. Appear striated. Often have cilia and goblet cells. Lines respiratory passageways.

(Pseudo = false Stratified = more than one layer)

Many cell layers. Top cells are flat. Can accumulate keratin. Outer layer of skin. Line oral cavity, vagina and anal canal.

2-3 layers. cube shaped cells. Line ducts of mammary glands, sweat glands, salivary glands and the pancreas

Top layer of elongated cells. Cube shaped cells in deeper layers. Line part of male urethra and part of the pharynx.

Composed of cells that are specialized to produce and secrete substances. 2 types: Endocrine glands are ductless (key word: hormone). Exocrine glands have ducts. Unicellular exocrine gland: composed of one cell, goblet cell. Multicellular exocrine gland: Composed of many cells. Sweat glands, salivary glands, ect. Simple and compound.

Merocrine secretion

Apocrine secretion

Holocrine secretion

Produced in golgi apparatus. Released by vesicles (exocytosis). Example: Sweat glands.

Types of secretion: fluid product. salivary glands, pancreas glands and sweat glands

Produced in golgi apparatus. Released by shedding cytoplasm. Example: Mammary glands.

Types of secretion: Cellular product. Portions of cells. Mammary glands. Ceruminous glands

Released by cells bursting, killing gland cells. Gland cells replaced by stem cells. Example: Sebaceous glands.

Types of secretion: Secretory products. Whole cells. Sebaceous glands

Most abudant tissue type. Many functions: bind structures, provide support and protection, serve as frameworks,fill spaces (loose connective), store fat, produce blood cells, protects against infections, helps repair damaged tissue. Has a matrix, has varying degrees of vasularity, has cells that usually divide.

Fibroblast - fixed cell,most common cell, large and star shaped, produces fibers.

Mast cells - fixed cell, release herapin (anticoagulant), releases histamine.

Goblet cells - found in columnar epithelial

Macrophages - Wandering cell, phagocytic, important in injury or infection.

Osteocytes - Found in bone

Chondrocytes - Found in cartilage

Red blood Cells

White blood cells

Platelets - Found in blood

Collagenous fibers - thick, composed of collagen, great tensile strength, abudant in dense CT, hold structurs together, tendons and ligaments.

Reticular fibers - very thin collagenous fibers, highly branched, form supportive networks.

Elastic fibers - fibers branch, elastic, vocal cords and air passages.

Not found in adults

Mesenchyme (embryonic stem cells) the first connective tissue in embryos

Mucous connective tissue - loose embryonic connective tissue.

Connective tissue: loose conenctive tissue, adipose tissue, reticular connective tissue, dense connective tissue, elastic connective tissue.

Specialized connective tissue: cartilage, bone and blood

Mainly fibroblasts, fluid gel like matrix, colleganous fibers, elastic fibers, bind skin to structures, beneath most epithelia, blood vessles nourish nearby epithelial cells, between muscles

Adipocytes, cushions, insulates, store fat, beneath skin, behind eyeballs, around kidneys and heart. Looks like bubbles.

Composed of reticular fibers, supports internal organ walls, walls of liver, spleen, lymphatic organs.

Packed collagenous fibers, elastic fibers, few fibroblasts, bind body parts together, tendons, ligaments, dermis. Poor blood supply

Abudant in elastic fibers, some collagenous fibers, fibroblasts,attachments between bones, walls of large arteries,airways and heart.

osteocytes in lacunae solid matrix, supports, protects, forms blood cells, attachment for muscles, skeleton

Rigid matrix, chondrocytes in lacunae, poor blood supply, 3 types:

Hyaline cartilage: most abundant, ends of bones, nose and respiratory passages, embryonic skeleton

Elastic Cartilage: flexible, external ear, larynx

Fibrocartilage: very tough, shock absorber, intervertebral discs, pads of knee and pelvic girdle.

fluid matrix called plasma, thee types of blood cells: red, white and platelets (cell fragments), transports, defends, involved in clotting, throughout body in blood vessles.

(Erythrocytes) responsible for transport of oxygen (and to a lesser degree, of carbon dioxide) in the blood. Accounts for about half the volume of whole blood and gives blood its color.

(Leukocytes) Help defend the body from infection and disease.

Monocytes: are phagocytes similar to the free macrophages in other tissues

Lymphocytes: uncommon in the blood but they are dominant cell type in lymph, the second type of fluid in CT

Eosinophilis and neutrophilis are phagocytes. Basophils promote inflammation much like mast cells in other CT

membrane enclosed packets of cytoplasm that function in blood clotting. These cell fragments are involved in the clotting response that seals leaks in damaged or broken blood vessles.

Lines passageways that have external connections, in digestive, respiratory, urinary and reproductive tracts, Epithelial surfaces must be moist (to reduce friction, to facilitate absorbtion and excretion), lamina propria

Lines cavities not open to the outside, are thin but strong, have fluid transudate to reduce friction, has a partietal protion covering the cavity, has a visceral portion (serosa) covering the organs.

Pleura - lines pleaural cavities, covers lungs.

Peritoneum - lines peritoneal cavity, covers abdominal organs.

Pericardium - lines pericardial cavity, covers heart.

Muscle cells are also called muscle fibers, contractile.

Attached to bones, striated and voluntary

Walls of organs, under skin, walls of blood vessels, involuntary, non striates.

Heart wall, involuntary, striated and intercalated discs.

Found in brain, spinal cord and peripheral nerves, functional cells are neurons, neuroglial cells support and bind nervous tissue components, conduction of nerve impulses.

Inflammatory response - the tissues first response to injury, signs and symptoms of the imflammatory response include: swelling, redness, heat and pain. Can be triggered by trauma or infection

speed and efficiency of tissue repair decreases with age due to: slower rate of energy consumption (metabolism), hormonal alterations, reduced physical activity

Chemical and structural tissue changes, thinning epithelial and connective tissue, increased bruising and bone brittleness, joint pain and broken bones, cardiovascular disease and mental deterioration

Cancer rates increase with age. 25% of all people in the US develop cancer. Cancer is the #2 cause of death in the US, environmental chemicals and cigarette smoke cause cancer.

The Integumentary system. 16% of body weight and 1.5-2 m2 in area.

2 parts the Cutaneous membrane (skin) and the accessory structures.

Epidermis; Dermis; Subcutaneous layer: (hypodermis) beneath dermis, also called the superficial fascial, some consider it not part of the skin.

Originate in the dermis, extends through the epidermis to skin surface - hair - nails - multicellular exocrine glands.

Protection of underlying tissues and organs

Excretion of salts, water and organic wasts (glands)

Maintenance of body temperature (insulation and evaporation)

Production of Melanin (pigment), keratin

Synthesis of vitamin D3

Storage of lipids

Detection of touch, pressure, pain and temperature.

Outermost layer of skin. Lacks blood vessles. Keratinized-made of dead cells. Thickest on palms and soles (0.8-1.4mm). Melanocytes provide melanin. Rests on basement membrane. Stratified squamous epithelial.

There are 5 Strata of keratinocytes in thick skin. From basal lamina to free surface:

1) Stratum basale. 2) Stratum spinosum. 3) Stratum granulosum. 4) Stratum lucidum. 5) stratum corneum.

Is attached to basement membrane by hemidesmosomes. Forms a strong bond betwen epidermis and dermis. Forms epidermal ridges (fingerprints). Dermal papillae (tiny mounds), increase the area of basement membrane, strengthen attachment between epidermis and dermis. Has many basal cells or germinative cells.

Merkel cells, found in hairless skin, respond to touch (triggers nervous system)

Melanocytes, contain the pigment melanin, scattered through stratum basale.

Produced by division of stratum basale, 8 to 10 layers of keratinocytes bound by desmosomes, cells shrink until cytoskeletons stick out (spiny), continues to divide, increasing thickness of spithelium, contain dendric (langerhans) cells, active in immune response

Stops dividing, starts producing: keratin, a tough fibrous protein, makes up hair and nails. Keratohyalin, dense granules, cross linked keratin fibers.

Found only in thick skin, covers stratum granulosum

exposed surface of skin, 15 to 30 layers of keratinized cells, water resistant, shed and replaced every 2 weeks.

The formation of a layer of dead, protective cells filled with keratin. Occurs on all exposed skin surfaces except eyes. Skin life cycle. It takes 7 to 10 days for a cell to move from stratum basale to stratum corneum.

White skin: lack of blood supply

Gray skin: Possible heart attack

Yellow skin: Jaundice or too much carotene

Blue skin: Lack of oxygen

Rash: allergic reaction

Dry skin: may be result of poor nutrition

Inflammation/blistering: burns

Genetic factors: varying amounts of melanin, varying size of melanin granules, albinos lack melanin. Physiological factors: dilation of dermal blood vessels, constriction of dermal blood vessels, accumulation of carotene, jaundice yellowing of skin. Environmental factors: sunlight, UV light from sunlamp, x-rays, darkens melanin.

Melanin protects skin from sun damage. UV radiation, causes DNA mutations and burns that lead to cancer and wrinkles. Skin color depends on melanin production not number of melanocytes.

On average 1.0-2.0mm thick. Contains dermal papillae. Binds epidermis to underlying tissues. Irregular dense CT. Contains muscle cells, nerve cell processes and specialized sensory receptors. Blood vessels. Hair follicles. Glands

Papillary layer: thin, superficial, dermal papillae here.

Reticular layer: 80% of dermis, cleavage, tension or Langer's lines are here.

Very strong, resist stretching but bend easily. Provide flexibility.

Permit stretching and then recoil to original length. Limit the flexibility of collagen fibers to prevent tissue damage.

Properties of flexibility and resilience

An inflammation of the papillary layer. Caused by infection, radiation, mechanical irritation, or chemicals (poison ivy). Characterized by itch or pain.

Sagging and wrinkles (reduced skin elasticity) are caused by: Dehydration, age, hormonal change and UV exposure.

Thickened tissue resulting from excessive stretching of skin due to: pregnancy and weight gain.

Cutaneous plexus: a network of arteries along the reticular layer.

Papillary plexus: capillary network from small arteries in papillary layer.

Venous plexus: capillary return deep to the papillary plexus.

Contusion: damage to blood vessels resulting in bruising.

Blood flow. Gland secretions. Senesory receptors, light touch - tactile corpuscles, located in dermal papillae, deep pressure and vibration - lamellated corpuscles, in the reticular layer

Lies below the integument. Stabilizes the skin. Allows seperate movement. Made of elastic areolar and adipose tissues. Connected to the reticular layer of integument by CT fibers. Few capillaries and no vital organs. The site of subcutaneous injections using hypodermic needles.

Distribution patterns determined by hormones. Reduced by cosmetic liposuction (lipoplasty)

Accesory structures of the skin originate from the epidermis and include: Hair follicles, nails, skin glands.

Hair follicles, sebaceous glands, sweat glands and nails, Integumentary accessory structures, derived from embryonic epidermis, located in dermis, project through the skin surface.

Epidermal cells, tube like depression, extends into dermis, 3 parts - hair root-hair shaft- hair papilla, dead epidermal cells, melanin, arrector pilli muscle.

The human body is covered with hair except: palms, soles, lips, portions of external genitalia.

Protects and insulates, guards openings against particles and insects, is sensitive to light and touch.

Located deep in the dermis, produces nonliving hairs, wrapped in a dense CT sheath, base is surrounded by sensory nerves (root hair plexus)

Arrector pilli: involuntary smooth muscle, causes hair to stand up, produces "goose bumps". Subaceous glands: lubricate the hair, control bacteria.

Hair root: lower part of the hair, attached to the integument. Hair shaft: upper part of the hair, not attached to the integument.

Begins at the base of the hair follicle, deep in the dermis. The hair papilla contains capillaries and nerves. The hair bulb produces hair matrix, a layer of dividing basal cells, produces hair structure, pushes hair up and out of the skin.

Medulla, the central core. Cortex, the middle layer. Cuticle, the surface layer.

As hair is produced, it is keratinized. Medulla contains flexible soft keratin. Cortex and cuticle contain stiff hard keratin.

Growing hair, is firmly attached to matrix. Club hair, is not growing, is attached to an inactive follicle. New hair growth cycle, follicle becomes active, produces new hair, club hair is shed.

Vellus hairs, soft, fine, covers body surface. Terminal hairs, heavy, pigmented, head, eyebrows, and eyelashes, other parts of body after puberty.

Produced by melanocytes at the hair papilla, determined by genes.

Sebaceous Glands (oil glands), holocrine glands, secrete sebum. 2 types of sweat glands, apocrine glands, merocrine (eccrine) glands, watery secretions.

Found in armpits, around nipples and groin. Secrete products into hair follicles. Produce products into hair follicles. Produce sticky, cloudy secretions. Break down and cause odors (due to bacteria). Surrounded by myoepithelial onto skin surface, squeeze apocrine gland secretions onto skin surface, in response to hormonal or nervous signal.

Merocrine (Eccrine) sweat glands, widely distributed on body surface, especially on palms and soles, coiled-tubular glands, discharge directly onto skin surface. Sensible perspiration, water, salts and organic compounds, functions of merocrine sweat gland activity: cools skin, excretes water and electrolytes, flushes microorganisms and harmful chemicals from skin.

Mammary glands- produce milk

Ceruminous Glands: Produce cerumen (earwax), protect the eardrum.

Protective coverings, 3 parts: nail plate, nail bed, lunula

Nail body: the visible portion of the nail, covers the nail bed. Lunula: the pale crescent at the base of the nail. Sides of nails: lie in lateral nail grooves, surrounded by lateral nail folds. Skin beneath the distal free edge of the nail: is the hyponychium (onyx=nail). Visible nail emerges: from the eponychium (cuticle), at the tip of the proximal nail fold.

repair of the integument following an injury: bleeding occurs, mast cells trigger inflammatory response, a scab stabilizes and protects the area, germinative cells migrate around the wound, macrophages clean the area, fibroblasts and endothelial cells move in, producing granulation tissue. Fibroblasts produce scar tissue, inflammation decreases, clot disintegrates, fibroblasts strengthen scar tissue,a raised keloid may form.

One of the major functions of the skin is to regulate body temperature, the skin does this by dilating or constricting blood vessels in the skin, regulation of body temperature is vitally important because even slight shifts can disrupt metabolic reactions, hypothermia-reduced body temperature due to cold; may result in frostbite. Hyperthermia-elevated body temperature may be due to excessive environmental temperature (heat stroke); usually due to infection (fever).

Negative feedback loop

Heat is a product of cellular metabolism-the most active body cells are the heat producers and include: skeletal muscle, cardiac muscle, cells of certain glands such as the liver. The primary means of heat loss is radiation, also there is conduction, convection and evaporation, elevated body temp results in fever. Fever can be caused by disease or environmental conditions - heat stroke.

First degree burn- superficial partial thickness

Second degree burn- deep partial thickness

Third degree burn- full thickness, autograft (from another part of the body), homograft (from another human), various skin substitutes, zenograft (from another species).

Skin becomes scaly, age spots appear, epidermis thins, dermis becomes reduced, loss of fat, wrinkling, sagging, sebaceous glands secrete less oil, melanin production slows, hair thins, number of hair follices decreases, nail growth becomes impaired, sensory receptors decline, body temp unable to be controlled, dimished ability to activate Vitamin D

Pediculosis-lice

Dandruff- dry skin

balding- death of hair follicle

Alopecia-chunks of hair loss

albinism-no pigment or form of

boils-large infected pimples

black heads-cellular debris in pores

freckles- sun exposed skin caused by melanocytes.

acne-a lot of infected pores, too much sebum