Oncology basics

• Unit 2 covers oncology, tissues, the integument, and the skeletal system.

Oncology

• Errors during DNA replication or translation can result in uncontrolled mitosis, also known as cancer.
• A tumor is an excess of tissue or swelling.
• Tumors are also known as neoplasms, meaning 'new growth'.
• Tumors can be benign, which are unlikely to spread, or malignant, which can metastasize, or spread.
• Both benign and malignant tumors can be fatal.
• Brain tumors are very dangerous.
• It is estimated that one in two Americans will develop cancer.
• Only one in five will die from it.
• Carcinomas affect epithelial cells.
• Sarcomas affect connective tissues such as osteosarcoma.
• Sarcomas are considered the worst kind of cancer.
• Transformation is the process of a normal cell becoming cancerous. Carcinogens are substances that can cause cancer through things we eat, drink or come into contact with, such as smoke and red dye 40.
• Oncogenes are genes that can cause cancer, like the BRCA gene.
• Oncogenes relate to heredity or genetics.
• Decreased immune function can also lead to cancer, particular for senior citizens and children and those with HIV or diabetes.
• Tumor suppressor genes can help prevent cancer.
• Many people have this gene but in some it’s turned off.
• Certain viral infections, such as HPV can also lead to cancer.
• The #1 carcinogen is smoking.

Cancer Diagnosis & Treatment

• Diagnosis involves looking for visible masses with the help of biopsies to help stage the cancer from 1 to 4.
• Weight loss is an indicator as well due to high nutrient demand from the cancer cells.
• Treatment involves surgical removal, radiation and chemotherapy.
• Angiogenesis inhibitors to block new blood vessels from forming and #targeted chemotherapy are also considerations.
• A vaccine is an injectable treatment.

Chemotherapy

• Chemotherapy works by killing rapidly generating cells, which include cancer cells at 90% but also healthy cells at 10%.
• Side effects include hair loss, pale skin, weight loss, nausea and decreased immune system.
• Very slow-dividing cells such as liver, neuron and heart cells are not effectively treated by chemo.

Histology

• Cells function together, creating tissues.
• Mitotic cancers are neuroglia cells leading to brain cancer.
• Cells require junctions to assist in functioning:
• Tight junctions.
• Gap junctions.
• Desmosomes.
• Tissues are classified into four main categories: Epithelium, Connective, Muscle and Nervous.
• Classification considers cell structure, function, and the amount of matrix.

Epithelium

• Epithelium is located on surfaces or glands and has apical/basal surfaces. Epithelial tissue has the characteristics of no matrix, avascularity, and a high rate of mitosis.
• Functions include protection, absorption, secretion, and sensation.
• Surface epithelium is defined by its layers and shape.
• Layers can be simple, stratified, or pseudostratified looking simple but is actually stratified structure.
• Shape can be squamous, cuboidal, columnar or transitional.
• Glands can be either endocrine, secreting to blood, or exocrine secreting to the surface.
• Endocrine glands produce hormones that enter the blood.
• Exocrine glands secrete onto a surface, either internal or external.
• Exocrine glands have 3 types of secretion modes:
• Merocrine: exocytosis.
• Apocrine: cell + vesicle
• Holocrine: entire cell.

Connective Tissue

• Connective tissue is abundant tissue that comes from the mesenchyme.
• Characteristics include having a matrix and being fluid, solid, or semisolid.
• It is vascularized except for cartilage/tendon.
• It has a nerve supply except for cartilage.
• Functions include storage, insulation, protection, transportation.
• Examples include bones and blood.
• Two main types of connective tissue include connective tissue proper, found in multiple organ systems, and specialized connective tissue, only found in 1 of the 11 systems.
• Adipose, bone and blood are examples of connective tissue.
• Blood stays inside the vessels.

Muscle & Nervous

• Muscle tissue has 3 types: Cardiac, Skeletal, and Smooth.
• Nervous tissue has 2 cell types:
• Neurons - which carry action potentials.
• Neuroglial cells - which support the nervous system.

Integumentary System

• The skin, also known as the integument, is the largest organ of the body comprising 7% of body weight.
• It is composed of 2 regions including the epidermis, dermis and hypodermis.
• Functions of the skin.
• Protection.
• Sensation.
• Temperature Regulation.
• Excretion.
• Vitamin D Production.
• The text says sunlight creates cholecalciferol made in the skin which turns into calcidiol in the liver and then calcitriol in the kidney. Calcitriol is the active form of Vitamin D needed for calcium absorption.
• The epidermis has two cell types including keratinocytes, which are 97% of the epidermis (yellow/tan color), and melanocytes which are gray color at the bottom of the epidermis.
• The text indicates the functions of keratinocytes which is waterproof our skin surface, and Melanocytes equals UV light.

Epidermis Layers

• The layers are composed of:

• Basale-single layer adj to basement membrane, contains melanocytes and keratinocytes, area of mitosis.

• Spinosum-8-10 layers; melanin transferred to keratinocytes.

• Granulosum-3-5 layers; nuclei degenerates; keratin production begins.

• Lucidum-3-5 layers; thick skin only; dead cells.

• Corneum-25-30 layers; flat dead cells completely filled with keratin.

• The stratum, basale is what is adjacent to the basement membrane.

• Areas prone to friction feature thicker skin including the lucidum layer and an increased number of layers to the s.corneum . Accumulation is defined as a callus.

Melanins

• Melanin is the pigment in the skin.
• Regardless of the amount of pigmentation, everyone has the same number of melanocytes.
• Melanin molecules vary in color:
• Red- Pheomelanin.
• Brown/black- eumelanin.
• Melanin is produced by melanocytes in the s. basale and have a peak production of 10 days after sun exposure.
• Melanin is made from the amino acid tyrosine with the help of the enzyme tyrosinase to form melanin.
• Melanin helps waterproof our skin surface and protect from UV light.
• Albinism symptoms are pale skin, red eyes, and sunburn.
• This is due to a lack of tyrosinase enzymes.
• Tanning has a duration of about 7 days in the corneum layer.
• Hemoglobin is a red pigment in RBCs visible through layers of the epidermis.
• Embarrassment causes red cheeks.
• Naturally red skin can be due to pale skin.

Dermis

• Fibroblasts in the dermis are located in the connective tissue.
• They produce elastin and collagen.
• The dermis is subdivided into papillary and reticular areas.
• Dermal papillae determine the shape of fingerprints.
• Tattoos are permanent due to ink in the reticular layer.
• Wrinkles form due to collagen collapse.
• Accessory skin structures (glands, hair and skin) and located in the epidermis and dermis.
• Sebaceous (oil) glands are connected to hair follicles and secrete sebum - which uses holocrine where cells are replaced.
• Sudoriferous (sweat) glands have 2 types:
• Eccrine/Merocrine glands are watery secretion, associated with temperature regulation around the neck.
• Apocrine glands are viscous secretions found in axilla and groin and associated with stress/excitement.
• Hormones are also found within the dermis.
• The apocrine gland secretes hormones that are attractants to the opposite sex.

Additional Glands

• Ceruminous glands are modified sweat glands in the external ear canal.
• These glands release the product cerumen via apocrine secretion. Mammary glands are also modified sweat glands that produce milk via apocrine secretion.

Hair

• Hair is composed of columns of dead keratinized epithelial cells.
• Protection (temperature, sensation) is one of the main functions.
• Regions include the hair shaft and root.
• Hair surrounds the follicle.
• The follicle base contains a bulb with mitotically active cells.

Hair Growth

• Hair growth occurs in cycles. Location and genetics determine length, growth, and resting periods.
• Eyelashes have 30-day growth cycles and pre-determined length.
• Scalp hair has 1-2 year growth cycles and grows forever.

Nails

• Nails are composed of tightly packed hard keratin and grow forever.
• Mitotically active cells are found in the nail root.
• The lunula is a thickened area of the nail covering the root; appears white.
• Nails have no resting period.

Hypodermis

• The hypodermis is technically not skin.
• It is also called the subcutaneous region.
• It contains adipose tissue and is a common site for injection administration.
• Skin helps in maintaining homeostasis:
• Too hot triggers eccrine glands.
• Too cold triggers hair.
• Intact skin is protective for homeostasis.
• Wound healing happens via:
• Primary intention for wounds that heal fast.
• Secondary intention for wounds that take longer.
• Deeper and wider wounds take longer.

Wound Healing

• Mitosis stops once there and is contacted inhibition.
• Scars form when fibroblasts in dermis invade into the defect and deposit collagen and are often lighter in skin tone.
• Keloids include excessive scar tissue formation and will come back if cut off
• Medications can be given transdermally across intact skin.
• Medication must be lipid soluble.
• Nicotine, birth control, fentanyl and hydrocortizone utilize this pathway. Burns are caused by heat, chemicals or radioactivity. First-degree burns only involve the epidermis and heal on its own. Second-degree burns involve the epidermis and part of the dermis. Third-degree burns involve the epidermis, dermis and part of the hypodermis, often are without pain, and require long healing.

Rule of 9's

• The Rule of 9's determines the amount of body surface area burned.
• Each body region has an associated percentage.
• It is especially useful with 3rd-degree burns to determine likelihood of systemic effects.
• Skin grafts take skin to help it heal Type include
  • Autograft - skin is transferred over from another area on the body
• Isograft which is skin from identical twin
• Another term for Isograft is called autologous but the skin can be grown Another type Homograft is where same species of skins are exchanged such skin from Fraternal twin or organ donors.
• Heterograft which is a skin transplant with different species.. Skin cancer is not always necessary cancer and some cancers are due to the amount of skin asymetrical Border = uneven edges Color = 2 or skin colors diameter - larger than tumor Evolution

Skin Cancer

• Asymmetry and uneven borders and diameter increase the chances 3 of the symptom are a signal to go to a Doctor Basal cell carcinoma is epithelium and made of tumors.
• 75% of all skin cancer derive from the stratrum basale, slow to mestasize Squamous cell carcinoma is keratinocyte and has stratum spinosoum. Also slow to mestasize Melanoma occurs from an life theartning metastasis that is from melanocytes Lastly Other skin Pathology include Descdubitus Bedsore / pressure point elderly Psorasis Rash/scaling-inflammed worst chemo Vitiligo Patches of skin lose their Ringworm Fungal infection (4,11)

Skeletal System

• Chapter 7 covers the skeletal system.
• The skeletal system is Composed of both bone and cartilage and is a Connective tissue #college senior that is Derived from mesenchyme
• Functions include storage storage
• protection Red and white blood cells are in the bone morrow

Cartilage

• Cartilage has Cartilage has h
• What cartilage The cell can be Cartilage has 3Types in this book. Matrix for this can be protein and sugar hyaline listed above/bone-like + rigid/trache + costal ribs Fibro cartilage is found in disks or pelvic for childhood Elastic is the most fleixble

Tissue Growth

Is important part of growth Apoposional growth is a top to bottom to do with walls layers cartilgenic

Bone

long long short heel flat irregular vertebal

compact type spngey epiphysis The growth plate Marrow part is with osteum

Ossesous Cell

Cartilage bone Bones cells osteo chondrial Bones blst, cite and clash

• osteo cite
• osteoblast which rebuilds sites

Caniculli

• Canilicular allow communication