Anatomy and Physiology Chapters 4-7
hair receptors
(nerve fibers) coil around the follicle and respond to hair movements
Stratum granulosum
3-5 layers of keratinocytes with dark-staining granules. Keratin filaments clump together and form a water-proofed layer. The cells die here as a result.
flat bones
Act as protective plates covering delicate organs (sternum and skull) or as a broad attachment point for muscles (scapula) Consist of two layers of compact bone enclosing a middle layer of spongy bone
dermis
Consists of fibrous connective tissue, is mostly collagen Well supplied with blood vessels, sweat glands, sebaceous (oil) glands, and nerve endings
Cartilaginous joints
Other name: amphiarthrosis Structure: adjacent bones are bound by cartilage Mobility: varies, but can be a little movement Examples: o pubic symphysis (where fibrocartilage joins the right and left bones together) o intervertebral discs (fibrocartilage joins consecutive vertebrae to each other)
Fibrous joints
Other name: synarthrosis Structure: adjacent bones are bound by collagen fibers Mobility: most have very little Examples: o skull sutures o joint between the radius and ulna (the interosseus membrane) o joint between the tibia and fibula
thermoregulation
The skin stabilizes body temperature by regulating heat exchange with the environment o blood flow near the skin is reduced to retain heat o blood flow near the skin is increased to prevent overheating
Dermal papilla
a bit of vascular CT that grows into the bulb and provides the hair with its sole source of nutrition
Hematoma
a bruise, a mass of clotted blood showing through the skin o can result from trauma, platelet deficiencies, anticoagulant drugs, or hemophilia
gland
a cell or organ that releases substances for use elsewhere in the body or for elimination from the body
Mineral deposition
a crystallization process in which osteoblasts extract calcium and phosphate from the blood and deposit it in the osseous tissue
hair follicle
a diagonal tube of epithelium and connective tissue that penetrates the dermis
tissue
a group of similar cells and cell products that work together to perform a specific function
albinism
a hereditary lack of pigmentation in the skin, hair and eyes due to an inability to synthesize melanin
epidermis
a keratinized stratified squamous epithelium composed of keratinocytes, dendritic, melanocytes, tactile, and stem cells
spongy bone
a porous lattice filled with blood-filled spaces. Is always found in the interior of a bone
resorption
a process in which the osteoclasts dissolve bone, releasing the minerals into the blood and making them available for other uses
stratum basale
a single layer of stem cells, keratinocytes, melanocytes and tactile cells
hair
a slender filament of keratinized cells that grows from a hair follicle Hair is made from a harder keratin than what's in the skin
Piloerector muscles
a small smooth muscle attached the hair follicle. When it contracts, pulls the follicle into a vertical position
jaundice
a yellowing of the skin and whites of the eyes o occurs in various liver diseases (cancer, hepatitis, cirrhosis and some blood diseases with a rapid rate of erythrocyte breakdown)
Erythema
abnormal redness of the skin (as in sunburn, exercise, hot weather, embarrassment)
cortex
beneath the cuticle, makes the bulk of hair
Cyanosis
blueness of the skin resulting from oxygen deficiency in the blood or reduced dermal blood flow in cold weather
keratinocytes
cells packed with keratin
dendritic cells
cells that alert the immune system to foreign invaders
medulla
centeal core that's only present in thick hairs (i.e.: eyebrows and lashes)
tendons
collagen bands that attach muscle to bone
ligaments
collagen bands that hold bones together at the joints
skeletal system
composed of bones, cartilage, and ligaments joined tightly to form a strong, flexible framework for the body
stem cells
continually divide to produce new keratinocytes
muscle tissue
description: Tissue composed of elongated, excitable cells function: Specialized for contraction and movement ex: Skeletal muscles, heart, walls of hollow organs and blood vessels
nervous tissue
description: Tissue containing excitable cells that can also generate a signal function: Specialized for rapid transmission of information to other cells ex: Brain, spinal cord, nerves
connective tissue
description: Tissue with more matrix than cell volume function: Usually specialized to support, bind, or protect organs. Blood is used for transport ex:Tendons, ligaments, cartilage, bone, fat, blood
epithelial tissue
description:Composed of layers of closely spaced cells function:Covers organ surfaces, forms glands, serves for protection, secretion and absorption ex:Epidermis, lining hollow organs, glands
Four tissue classes
epithelial, connective, nervous and muscular
yellow bone marrow
fatty substance that fills long bones in adults
periosteum
fibrous connective tissue sheath covering the external surface of a bone
ossification
formation of bone
secretion
gland's product if it is useful
First gap phase (G1)
he interval between cell division and DNA replication
compact (dense) bone
is solidly filled with opaque matrix. Is always found on the surface of a bone Organized into osteons (cylindrical units of bone structure) Layers of matrix called lamellae arranged concentrically around a central canal, which contains blood vessels and nerves
Hair matrix
just above the dermal papilla, is the exclusive site of cellular mitosis and hair growth
serous membrane (serosa)
line the thoracic and abdominal cavities, cover the external surfaces of organs composed of a simple squamous epithelium produce a thin, watery fluid
mucous membranes
line tracts of the body that open to the exterior environment (digestive, respiratory, urinary and reproductive tracts) are covered by mucus that traps bacteria and foreign particles
hypodermis
looser CT and adipose tissue binds the skin to underlying muscles subcutaneous fat pads the body, serves as a energy reservoir, provides thermal insulation
Stratum spinosum
many layers of keratinocytes and some dendritic cells; these keratinocytes stop dividing and start synthesizing keratin
Epiphyseal lines
mark former growth zones from childhood
osteocytes
mature bone cells (former osteoblasts) that have become trapped in the matrix they deposited
matrix
non-living extracellular material
merocrine sweat glands
numerous, and especially abundant on palms, soles and forehead ducts lead to skin surface; produce watery perspiration that serves to cool the body;Sweat has a pH ranging from 4-6
red bone marrow
o Produces red blood cells and platelets o fills all bones in children, fills spongy bone in adults
apocrine sweat gland
o ducts lead onto hair follicles o secretion contains more fatty acids than merocrine sweat glands o especially respond to stress and sexual stimulation o produce pheromones (chemicals that influence the physiology or behavior in other members of the species)
cerumionous glands
o found only in the auditory canal o secretion combines with sebum and dead epidermal cells to form cerumen (ear wax) o ducts lead to the skin surface o cerumen keeps eardrum pliable, waterproofs the auditory canal and has a bactericidal effect
osteoblasts
o function to synthesize and deposit matrix o develop from osteogenic cells, lie on the bone surface
osteoclasts
o large, multinucleated, bone-dissolving cells o lie on the bone surface
sebaceous glands
o produce an oily secretion (sebum) o short ducts open into a hair follicle o Sebum keeps the skin and hair from becoming dry, brittle and cracked
Osteogenic cells
o stem cells that occur on the bone surface o they are the only cells capable of dividing and making more bone cells
necrosis
pathological death of tissue due to trauma, toxins, infection, etc. Often spreads
serous gland
produce a thin, watery fluid (like sweat, milk, tears)
melanocytes
produce the dark pigment melanin, which protects the deeper tissues from UV rays in the sunlight
Intramembranous Ossification
produces flat bones of skull a. Begins with a sheet of mesenchyme (embryonic connective tissue) b. Osteoblasts deposit immature bone matrix ("osteoid"), which then hardens c. Osteoblasts trapped in the matrix become osteocytes d. Spaces where there isn't bone fills with blood vessels and red marrow
Endochondral Ossification
produces most of the bones in the body a. Begins with hyaline cartilage b. Formation of primary ossification center (in the diaphysis), bony collar and periosteum c. Vascular invasion, formation of the primary marrow cavity d. Appearance of the secondary ossification center e. Secondary ossification center develops in the epiphyses f. Vascular invasion, formation of the secondary marrow cavity g. Epiphyseal plates close
apoptosis
programmed cell death, the normal death of cells that have completed their function. This is caused by lysosomes that degrade the cell's DNA and proteins does not spread from cell to cell
Parathyroid hormone (PTH)
raises blood calcium by stimulating bone resorption by osteoclasts
Calcitriol (Vitamin D)
raises blood calcium by stimulating osteoclasts and promoting calcium absorption from food
exocrine gland
release a secretion onto an epithelial surface release a secretion through a duct Examples: sweat glands, salivary glands, mammary glands, liver Further classified by the type of secretion
endocrine glands
release their products into the bloodstream, do not have ducts the secretion is a hormone, which serves as a chemical signal to other organs Examples: pituitary gland, thyroid gland, adrenal glands
mucous gland
secrete a protein that absorbs water and becomes mucus (secreted on the respiratory and digestive tracts)
tactile cells
sensory cells for the sense of touch
atrophy
shrinkage of a tissue through a loss in cell size or number, due to lack of use or aging
why can few infections organisms penetrate the skin?
skin cells are packed with a tough protein (keratin) skin is dry skin is covered with an acidic film
bone marrow
soft bloody or fatty material enclosed in bones
what type of cells protect the body from abrasion?
stratified squamous cells; linked by desmosomes
functions of skeleton
support; protection; movement; blood formation; storage
cuticle
surface of the hair
pallor
temporary pale or ashen color, results when there is little cutaneous blood flow and skin color is dominated by white dermal collagen o can result from emotional stress, circulatory shock, cold temperatures, or severe anemia
reticular layer
the bulk of the dermis, zone of dense irregular CT. Is very tough (think of the leather of animal hides, which is made from this layer)
differentiation
the development of specialized tissue from stem cells
Cytokinesis:
the division of the cytoplasm
Shaft/diaphysis
the elongated midsection of long bones, provides leverage
Head/epiphysis
the expanded end of a long bone. Functions to strengthen a joint and provide added surface area for a tendons and ligaments
osseous tissue
the hard, calcified tissue of a bone Osseous tissue consists of cells and matrix. Like other connective tissues, the matrix is made of fibers and ground substance
Medullary cavity
the hollow space(s) inside of a bone, filled with marrow
Second gap phase (G2)
the interval between DNA replication and cell division
Synthesis phase (s)
the period in which a cell replicates its DNA The DNA is unzipped and the nitrogen bases are exposed DNA polymerase (an enzyme) assembles complementary nucleotides for each strand
Mitotic phase (M)
the period in which a cell replicates its nucleus and divides its DNA into two identical sets Prophase, Metaphase, Anaphase, Telophase
hemoglobin
the red pigment of blood imparts a reddish or pink hue to the skin as blood vessels show through the dermal collagen
fibrosis
the replacement of damaged tissue with scar tissue (collagen) The tissue is held together but does not have its normal function
regeneration
the replacement of dead or damaged cells by the same type of cells as before, thus restoring the normal function Many epithelial tissues are excellent at this (especially the skin and liver)
histology
the study of tissues
Dermal papillae
the upward waves of connective tissue that interlock with the epidermis o this reduces slippage of the epidermis across the dermis, and also produces fingerprints
Articular cartilage
thin layer of hyaline cartilage that covers the ends of bones in a joint
endosteum
thin layer of reticular connective tissue lining that separates the marrow from the bone
Papillary layer
thin zone of areolar connective tissue (CT) beneath the epidermis, filling the dermal papillae
stratum lucidum
this is only present in the thick epidermis of the palms and soles. It is a thin, clear layer of dead cells
hyperplasia
tissue growth though cell multiplication
Stratum corneum
up to 30 layers of dead, keratin-packed keratinocytes. The dead cells exfoliate (flake off) from the surface
excretion
waste product of a gland
carotene
yellow pigment acquired from foods, can become concentrated in the stratum corneum and hypodermis
