unit 2 anatomy based on my notes

What does the integumentary system consist of?

Skin, hair, oil glands, sweat glands, nail, sensory receptors

What are the functions of the integumentary system?

Maintain temperature, convert inactive vitamin D to active form, provide sensory information, maintain homeostasis

What are the layers of the skin?

Epidermis, dermis, subcutaneous layer

Describe the structure of the epidermis.

Avascular, thin compared to the dermis, contains epidermal ridges and sweat pores

What are the cell types found in the epidermis?

Keratinocytes, melanocytes, dendritic cells, tactile epithelial cells

What is the function of keratinocytes?

Produce keratin, a tough fibrous protein that protects the skin

What is the function of melanocytes?

Produce melanin, which protects keratinocytes from UV damage

What is the function of dendritic cells?

Participate in immune response against microbes that invade the skin

What is the function of tactile epithelial cells?

Detect touch sensations

What are the two types of skin?

Thin and thick

Where is thin skin found?

Covers all body regions except palms, palmar surfaces of digits, and soles

Where is thick skin found?

Covers the palms, palmar surfaces of digits, and soles

What are the sublayers of the epidermis?

Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

Describe the stratum basale.

Deepest layer, contains simple cuboidal cells, lots of mitosis, keratinocytes begin here

Describe the stratum spinosum.

Located above the stratum basale, contains 8-10 rows of keratinocytes, bundles of keratin begin to be made

Describe the stratum granulosum.

Contains granules, last layer of live keratinocytes before apoptosis, granules become visually prominent

Describe the stratum lucidum.

Present only in thick skin, such as soles and palms, looks light

Describe the stratum corneum.

Consists of dead keratinocytes and is mostly layers of keratin

What is the dermis?

Dense irregular connective tissue that supports the epidermis.

What is the function of the dermis?

To provide great tensile strength and support the avascular epidermis.

What are the two layers of the dermis?

Papillary and reticular.

Describe the papillary layer of the dermis.

Superficial portion of dermis, consists of areolar connective tissue with thin collagen and fine elastic fibers.

What structures are found in the papillary layer?

Dermal papillae, blood capillaries, tactile corpuscles, and free nerve endings.

Describe the reticular layer of the dermis.

Deeper portion of dermis, consists of dense irregular connective tissue with thick collagen and some elastic fibers.

What structures are found in the reticular layer?

Adipose cells, hair follicles, nerves, sebaceous glands, and sudoriferous glands.

What is hemoglobin?

Red pigment found in red blood cells.

What is carotene?

Yellow-orange pigment stored in the stratum corneum and adipose tissue.

What are the two types of pigments?

Eumelanin (brown to black) and pheomelanin (yellow to red).

What is albinism?

A condition where the individual cannot produce melanin, resulting in pale/pink skin, white blonde hair, and light blue eyes.

What is vitiligo?

A chronic disorder characterized by the loss of function of melanocytes, resulting in irregular white spots across the skin.

What is the composition of hair?

Dead, keratinized epidermal cells bonded by extracellular proteins.

What determines the darkness and distribution of hair?

Genetic and hormonal influences.

What are the parts of hair?

Shaft (above the skin surface), root (below the skin), and follicle (epithelial and dermal tissue surrounding the root).

What is the hair bulb?

A papilla where blood vessels can enter to support hair growth.

What is the growth of hair called?

Hair growth.

What happens during the hair growth stage?

Cells of matrix divide, majority of time is spent in this stage.

What happens during the regression stage of hair growth?

Hair moves away from the blood supply in papillary and follicle atrophies.

What happens during the resting stage of hair growth?

Old hair root falls out; new growth begins using the same follicle.

What is lanugo?

Downy hair that covers the fetus.

What is terminal hair?

Long, coarse, heavily pigmented hair. Found on scalp, eyebrows, armpits, and groin after puberty.

What is vellus hair?

Short, fine, pale hairs. Found on women's bodies.

What causes dark colored hair?

Mostly eumelanin.

What causes blond or red hair?

Variants of pheomelanin.

What causes gray hair?

Progressive decline of melanin production.

What causes white hair?

Lack of melanin, accumulation of air bubbles.

What are sebaceous glands?

Oil glands that produce sebum to keep hair from drying out and prevent excessive drying of skin.

What are sudoriferous glands?

Eccrine sweat glands that produce sweat for thermoregulation, and aprocrine glands that are active during emotional sweating.

What are ceruminous glands?

Modified sweat glands located in the ear canal.

What are nails made of?

Tightly packed hard, dead, keratinized epidermal cells.

Where are epidermal ridges present?

Only on thick skin.

Where are hair follicles present?

Only on thin skin.

Where are sebaceous glands located?

On thin skin, not thick skin.

Where are sudoriferous glands more numerous?

On thick skin, but there are some on thin skin.

Are sensory receptors sparser on thin or thick skin?

Sparser on thin skin and denser on thick skin.

What are the functions of skin?

Thermoregulation and adjustment of blood flow to the dermis.

What happens to blood vessels in the dermis when body temperature is increased?

They dilate.

What happens to blood vessels in the dermis when body temperature is decreased?

They constrict.

What is the function of blood reservoir in the dermis?

To store blood.

How much blood can the dermis hold?

About 8-10% of the body's blood volume.

What is the main function of the dermis?

Protection.

What are the different protective components found in the dermis?

Keratin, lipids released by lamellar granules, sebum, acidic sweat, melanin, macrophages.

What are the different cutaneous sensations?

Tactile sensations (touch, pressure, vibration, tickle), thermal sensations (warm, cool), pain.

What substances are excreted through the skin?

Water, salts, carbon dioxide, ammonia, urea.

What is absorption in the context of the skin?

The passage of material from the external environment into body cells.

Which type of substances can penetrate the skin?

Lipid-soluble materials.

What are some examples of substances that can be administered through the skin?

Nitroglycerin, estradiol, nicotine, fentanyl.

What is the role of the skin in the synthesis of vitamin D?

The precursor of vitamin D is activated by UV rays in sunlight, then modified in the liver and kidneys to produce the active form of vitamin D (calcitriol).

What are the functions of vitamin D?

Enhances immune function and aids in the absorption of calcium from foods in the gastrointestinal tract.

What are the different phases of deep wound healing?

Inflammatory phase, migratory phase, proliferation phase, maturation phase.

What happens during the inflammatory phase of wound healing?

Vascular and cellular response to eliminate microbes, foreign material, and dying tissue.

What happens during the migratory phase of wound healing?

Epithelial cells migrate beneath the clot to bridge the wound, forming a scab and producing granulation tissue.

What happens during the proliferation phase of wound healing?

Extensive growth of epithelial cells, deposition of collagen, and growth of blood vessels.

What happens during the maturation phase of wound healing?

Scab sloughs off, collagen fibers become more organized, and blood vessels are restored.

What is the main function of the skeletal system?

To provide support and protection, facilitate movement, produce blood cells, and store minerals.

What is bone?

An organ made up of different tissues.

What is the skeletal system?

The entire framework of bones and cartilages.

What are the functions of the skeletal system?

Support, protection, movement, mineral homeostasis, blood cell production, and fat storage.

What are the parts of a long bone?

Diaphysis, epiphysis, metaphysis, articular cartilage, periosteum, medullary cavity, and endosteum.

What is the histology of a bone?

Bone contains an extracellular matrix composed of water, collagen, and mineral salts.

What are the main minerals found in bone?

Calcium and phosphorus.

What are the four types of bone cells?

Osteoprogenitor cells, osteoblasts, osteocytes, and osteoclasts.

What do osteoprogenitor cells do?

They are bone cells capable of cell division and develop into osteoblasts.

What do osteoblasts do?

They are bone-building cells that secrete matrix and initiate calcification.

What are osteocytes?

Mature osteoblasts that are surrounded by their own matrix in a lacuna.

What do osteoclasts do?

They remodel bones and cause them to release calcium through bone resorption.

What is the composition of the extracellular matrix in bone?

Approximately 15% water, 30% collagen, and 55% mineral salts.

What are hydroxyapatite crystals?

Crystals formed by the combination of calcium phosphate and calcium hydroxide in bone.

What is the function of the periosteum?

It is the connective tissue surrounding the diaphysis of a long bone.

What is the function of the medullary cavity?

It is the hollow space within the diaphysis of a long bone.

What is the function of the endosteum?

It is the thin membrane lining the medullary cavity of a long bone.

What is the function of articular cartilage?

It covers the epiphysis of a long bone at joints.

What is the function of the metaphysis?

It is the region between the diaphysis and epiphysis of a long bone.

What is the function of the diaphysis?

It is the bone shaft of a long bone.

What are osteoclasts?

Cells that digest bone and release calcium and phosphorous.

What is compact bone?

Strongest bone that provides protection and support.

What is spongy bone?

Lightweight bone that provides tissue support and contains spaces filled with bone marrow.

What are periosteal arteries?

Arteries that enter the diaphysis through perforating canals, accompanied by nerves.

What is the function of periosteal veins?

To accompany periosteal arteries.

What is the nutrient artery?

A large artery that enters the center of the diaphysis through a nutrient foramen.

What is the function of nutrient veins?

To exit the diaphysis through the nutrient foramen.