AP Quiz 3 Flashcards
Hair Growth Cycle
A repeating cycle
Anagen (.3 mm/day in young adult, lasts 6-8 years in young adult)
Catagen (2-3 weeks)
Telogen (resting stage, 1-3 months)
Alopecia
thinning or baldness
Patterned Baldness
Sex-influenced trait expressed only with high levels of testosterone
Hirsutism
excessive hair growth due to hormonal imbalance (ovary or adrenal cortex problem)
Hair color
due to melanin from melanocytes in hair bulb)
Variation in hair color due to melanin binding to different compounds
White hair
due to air in medulla (since the cells aren’t bound as close together) and loss of pigment in the cortex
Cutaneous glands
sweat glands (eccrine and apocrine)
Sebaceous glands
Ceruminous glands (ear wax)
Mammary glands
Apocrine Sweat gland
produce sweat containing fatty acids; found near hair follicles and respond to stress and sex
Found in armpit, around nipples, and in pubic region
Secrete products into hair follicles or directly onto the surface
Begins functioning at puberty
apocrine
in the secretion, some of the cells are broken down, meaning that some of the cytoplasm is lost
Eccrine glands
Simple tubular glands (merocrine) – there are millions and they cool the body
not associate with follicles
Sebaceous glands
oily secretion called sebum that contains broken down cells (always going to be connected to a hair)
duct opens into hair follicle
Ceruminous glands
only found in external ear canal
secretion combines with sebum to produce earwax
function: waterproof, keeps eardrum flexible, and its bitterness repels mites and other pests
Mammary glands
only activated by pregnancy
secondary sexual characteristic of females
mammary glandular tissue found only during lactation and pregnancy
Structure of nail
tightly packed keratinized cells
nail body (visible portion pink due to underlying capillaries, free edge appears white)
Nail root (lunae is white due to thicken stratum basale)
Eponychium (cuticle) – stratum corneum layer
Causes of skin death due to burns
fluid loss, infection, and effects of dead tissue
Degrees of burns
1st: only epidermis (red, painful, and edema)
2nd: epidermis and part of dermis (blistered)
3rd: epidermis, dermis, and more is destroyed (often requires grafts or fibrosis and disfigurement may occur)
Treatment for Burns
fluid replacement and infection control
Bone
dynamic, continually remodeling
connective tissue with hardened matrix (composed of calcium phosphate)
Makes up skeletal system
What are bones composed of?
bone tissue, marrow, cartilage, and perisoteum
Functions of bone
supports and protects soft tissue
attachment site for muscles making movement possible
storage of calcium and phosphate (mineral homeostasis, they can be broken down to give back to the body)
bone cell production (occurs in red bone marrow thru process called hemopoiesis)
Energy storage in yellow bone marrow
Classification of bones
bone shapes:
long, short, flat, irregular, short, and sesamoid
Sesamoid bone
Bone embedded within a tendon
What are the internal tissues of a flat bone?
External and internal surfaces of flat bone that are composed of compact bone
Middle layer is spongy bone (dipole) without a marrow cavity
A blow to the skull may fracture outer layer and crush the dipole, but it won’t harm the inner compact bone
Anatomy of a long bone
Diaphysis = shaft
Epiphysis = one of the ends of a long bone
Metaphysis = growth plate region where the diaphysis connects to the epiphysis
Epiphyseal plate/line = area b/n epiphysis and metaphysis, responsible for longitudinal growth of bones
Hyaline cartilage acts as shock absorber, over the ends of the long bone
Medullary cavity = marrow cavity
Endosteum = lining of marrow cavity
Periosteum
tough membrane covering bone fibrous layer = dense irregular CT Osteogenic layer (inner layer or cellular layer) = bone cells and blood vessels that nourish or help with repairs
Structure of Periosteum
Two Layers
inner cellular-bone cells that nourish and help with repairs
outer fibrous, made of dense irregular CT
What are the general features of the bones?
Shaft (diaphysis) = compact cylindrical bone with marrow cavity lined with endosteum
Enlarged ends are spongy bone covered with a layer of compact bone (enlarged to strengthen joint and provide for attachment of tendons and ligaments)
Joint surface covered with articular cartilage
Remainder of bone covered with periosteum
Epiphyseal plate or line depends on age
Spongy Bone
Marrow cavity and spaces within spongy bone that contains either red bone marrow (blood cell formation)
Yellow bone marrow (lipid storage, more common in older age)
Endosteum
lines the marrow cavity
contains osteoblast, osteogenic cells, and osteoclast
What are the cells of osseous tissue?
Osteogenic cell
Osteoblast (forms bone matrix)
Osteocyte (maintains bone tissue)
Osteoclast (functions in resorption and breakdown of bone matrix)
Osteogenic (osteoprogenitor) Cells
resides in endosteum, periosteum, or central canals
Arises from embryonic fibroblasts and becomes the only source for new osteoblasts
Multiplies continuously and differentiates into different osteoblasts (more occurs based on stress or fracture responses)
Osteoblasts
Form and help mineralize organic matter of matrix
make and release proteins and other organic components of the bone matrix
Constantly adding to matrix
Osteocytes
osteoblasts that have become trapped in the matrix they form
mature bone cells that accounts for most of cell population
Each occupies lacuna (pocket sandwiched between layers (lamellae –> collagen fibers) of matrix
Canaliculli
narrow passageways that penetrate the lamellae
How are cells in lacunae connected?
they’re connected by gap junctions inside canaliculi
Signal osteoclasts and osteoblasts about mechanical stresses
Osteoclast
type of bone cell that removes and recycles bone tissue
Multinucleated cell that secretes acid and enzymes to dissolve bone matrix
Important for regulation of calcium and phosphate concentrations in body fluids
NOT related to osteoprogenitor cells –> from bone marrow from fusion of 3-50 same stem cells that make monocytes
Resides in resorption bays (pits) that they have eaten into surface of bone
Constantly removing matrix
Osteon
Basic structural unit
Cylinders of tissue formed from layers (concentric lamellae) of matrix arranged around central canal holding blood vessel
Connected to each other via osteocytes
Connected to blood supply by tiny cell processes in canaliculi
Compact bone structure
collagen fibers within each lamellae forms spiral that adds strength and resiliency
Compact bone
Perforating canals or Volkmann canals (vascular canals perpendicularly joining central canals)
Circumferential or outer lamellae
Composition of matrix of osseous tissue
85% hydroxyapatite (crystallized calcium phosphate salt) (2/3)
10% calcium carbonate and other minerals (fluoride, sulfate, potassium, and magnesium) (1/3)
Bone Marrow
Soft tissue that occupies medullary cavity of long bone or spaces amid the trabeculae of spongy bone
Red Marrow
Looks like thicc blood
mesh of reticular fibers and immature cells
hemopoietic (produces blood cells)
found in vertebrae, ribs, sternum, pectoral girdle, etc
Found in kids because they’re growing, not in adults
Contains stem and functional blood cells
Takes part in distruction of old erythrocytes (old red blood cells)
Ossification
Replacing other tissues with bones
2 types (intramembranous and endochondral)
“Skull needs to ossify fast” (it’s protecting brain)
“Kids better bounce not break” (kids’ long bones are more cartilage based, which changes later on)
Intramembranous (dermal) ossification
Occurs in deep dermis and produces “dermal bones” (mandible, flat bones of skull, and clavicle)
Formation of dermal ossification
- ) Mesenchymal cells aggregate: differentiate to osteoblasts, surround themselves with matrix to make osteocytes, and develop projections called spicules
- ) Blood vessels grow into area to supply osteoblasts, spicules connect to trap blood vessels inside bone, and matrix calcifies into trabeculae with spaces holding red bone marrow
- ) Mesenchyme condenses as periosteum at the bone surface, spongy bone develops and remodeled into osteons of compact bones, periosteum, or marrow cavities
Cartilage in embryo
more prevalent than in adult since skeleton is initially mostly cartilage
bone replaces cartilage in late fetal and childhood periods
Bone growth
bone will continue to increase in length so long as epiphyseal cartilage continues to grow at epiphyseal surface
Bone growth
bone will continue to increase in length so long as epiphyseal cartilage continues to grow at epiphyseal surface
How can you tell how old someone is when they die?
Cartilage cells continue to divide and grow, lengthening bone and being replaced by bone cells
at completion, the epiphyseal line sets in after they reach their set height
What is the distinguish of growth between long and flat bones?
Long bone are mainly endochondral ossification
Flat bones are mainly dermal ossification
The metaphysis
the place between head and shaft of bone (epiphyseal plate)
Bone growth in length
cartilage cells produced by mitosis on epiphyseal side of plate, they’re destroyed and replaced by bone on diaphyseal side of plate
Functions of calcium and phosphate
Phosphate: component of DNA, RNA, ATP, phospholipids, and acid base buffers
Calcium: communication b/n neurons, muscle contractions, blood clotting, and exocytosis
How to maintain calcium homeostasis?
Calcitonin – reduces Ca in blood (if greater 11 milligrams/deciliter)
Calcitriol and PTH – increases Ca in blood (if less than 8.5 milligram/dL)
Remember: osteoclasts break down bones to increase concentration in blood; intestines also play role since they break down food and send Ca to blood
Calcitonin Hormone
Secreted by C cells of thyroid
reduces osteoclast activity as much as 70% in 15 minutes
increases number and activity of osteoblasts
important role in children, little known effect in adults
(although may be useful in reducing osteoporosis effects)
Calcitriol (activated Vitamin D)
produced from UV radiation converted via liver and kidney
Stimulates intestine to absorb calcium, phosphate, and magnesium, weakly promotes urinary reabsorption of calcium ions
Parathyroid hormone
secreted by parathyroid glands on posterior surface of thyroid gland
binds to osteoblasts to release osteoclast stimulating factor that stimulates osteoclast multiplication and activity
Promotes calcium reabsorption in kidney (meaning calcium can be put back in blood), calcitriol synthesis in kidneys, and inhibits collagen synthesis and bone deposition by osteoblasts
