Lecture I 1st half histology and tissues Flashcards
sebaceous galants
Sebaceous glands are flask-shaped and have short ducts opening into hair follicles, Holocrine secretion style , Sebum—oily secretion of sebaceous glands onto skin surface
stratum granulosum
four thin five thick. more in thick than in thin. keratinocytes contain dark-staining granules
Stratum granulosum- four thin five thick
Keratohyalin granules release filaggrin binds keratin into coarse, tough bundles, to prevent water
Cells produce tough envelope proteins beneath their membranes
Membrane-coating vesicles release lipid mixture that spreads out over cell surface and waterproofs it
Keratinocytes’ organelles degenerate and the cells die
What is positive feedback?
• Can sometimes be dangerous (fever)- positive feedback fetus’ head pushes against cervix, nerves send signals to brain, brain stimulates pituaitary to secrete oxuytocin, oxytocin stimulates uterin contraction, fetus’ head applies more pressure to cervix and cycle repeats, strengthen.
epithelial cut
multiply migrate beneath scan scar tissue Nat show while undergoing fibrosis remodeling several weeks to two years
stratified epithelial
o stratified: Range from 2 to 20 or more layers of cells
o Some cells rest directly on others
o Named for the shapes of their apical surface cells
o 4 types
o Stratified squamous (looks like smooth muscle but cells below apical have different shapes and have connective tissue underneath)
o Stratified cuboidal
o Stratified columnar
o Transitional
short bones
wrist or ankle
elastic cartilage
conspicuous elastic fibers. weblike mesh and lacunae, covered by perichondreium, external ear epiglottis, provides flexible organic support
osteocytes
tiny lacunae between lamellae occupied by mature bone cells
types of bones
Flat bones, Long bones, Short bones, Irregular bones, Types, Spongy (cancellous bone loosely organized-tribecular covered in pericneum)), Compact (dense outer shell of bone, harder outer cover)
hair issues?
Alopecia- thinning of hair or baldness aging
Pattern baldness- allele for it dominant hair lost unevenly along scalp mostly men because high level oftestoterone required
Hirsutism- excessive or undesirable hair growth ovarian tumors or hypersecretion testosterone by adrenal cortex
What are cranial, post-cranial, axial, appendicular?
cranial (skull) and post-cranial (below hips)
axial (orange skull, spine, and sacram of pelvis, rib cage (thorax), and sternum, and appendicular skeleton lumbs and conection portions of that
epidermis
keratinized stratified squamous epithelium. lacks blood cells, sparse nerve endings for touch and pain. dead cells packed w/ tough protein keratin. lacks blood vessels and depends on diffusion of nutrients from underlying connective tissue, sparse nerve endings in dermis.
periosteum
a membrane that lines the outer surface of all bones, except at the joints of long bones. Perichondrium-a layer of dense irregular connective tissue which surrounds the cartilage of developing bone; Once vascularized, the perichondrium becomes the periosteum.
bone covered w/ sheath, tough outer fibrous layer of collagen and inner osteogenic layer (growth and healing) of bone-forming cells w/ perforating collagen fibers throughout providing strong attachment and continuity from muscle to tendon to bone
covers bone as whole similar to perichondrium of cartilage.
metaphysis
growth plate where bone is going to gain length.
first-degree
only epidermis, redness, edema, swelling, and pain
disuse atrophy
from lack of use
chondroblasts
(build matrix of cell exclude layers and bexome when trapped by matrix creating) . product cartilage secrete matrix surrounded till they become lacunae.
chondrocytes
(made from xhondroblasts communication within cells) heals slowly
once enclosed by lacunae cells are chondrocytes devoid of blood capillaries diffiusion have glycosaminoglycans and collagen classified hyalne, elastic, and fibrocartilage. elastic and hylane surrounded by perichondrium sheath of dense irregular connective tissue reserve population chondroblasts between perichondrium and cartilage allows to grow cap ends of long bones
• four primary tissues
mass of similar cells and cell products that form a discrete region of an organ and performs specific function: epithelial, connective, nervous and muscular tissue.
long bones
humerus, fibula, metacarpals, metatarsals, and phalanges act as levers acted upon by skeletal muscle to produce major body movements
outside of osseous w/ compact dense bone enclosing medullary cavity (bone marrow). ¾ bone
other pigments?
Hemoglobin—pigment in red blood cells. closer on lips
Carotene—yellow pigment acquired from egg yolks and yellow/orange vegetables. concentrated in stratum corneum and subcutaneous fat skin of feet and calluses of heel
cyanosis-blueness of skin from oxygen deficiency.
erythemia- abdnormal redness of skin. exercise hot weather, sunburn, anger, and embarrassment. increased blood flow in dilated cutaneous blood vessels
pallor- pale or ashen color occurs when little blood flow through skin white of dermal collagen shows through, emotional stress, low bp, shock, cold, anemia.
albinism- pale genetics
jaundice- excessive bilirubin- hemoglobin breakdown in excess
hematoma- bruise clotted blood.
parts of nail?
Nail plate—hard part of the nail.
Free edge: overhangs the fingertip
Nail body: visible attached part of nail
Nail root: extends proximally under overlying skin
Nail fold—surrounding skin rising above nail
Nail groove—separates nail fold from nail plate
Nail bed—skin underlying the nail plate hyponychium,
Nail matrix—growth zone (mitotic) of thickened stratum basale at proximal end of nail. mitosis in the matrix accounts for growth of nail obscuring underltying dermal blood vessels w/ lunule proximal end white crescent
Eponychium (cuticle)—narrow zone of dead skin overhanging proximal end of nail
2 layers of hypodermis
Hypodermis & Subcutaneous fat (predominately of adipose tissue, energy reservoir and thermal insulation in certain areas) . areolar and adipose tissue, pad body and bind skin to everything underneath has to go through this to below otherwise drugs don’t go through. subcutaneous fat thicker in women thinner in kids and elderly
fibrous tissue
(areolur) most diverse slender whispy branches fibers and ground substance forming matrixLocation: Underlies epithelia, in serous membranes, between muscles, passageways for nerves and blood vessels.)
exocrine and endocrine
o Unicellular glands can be either
o Some organs have both endocrine and exocrine functions
• Examples: liver, gonads, pancreas
holocene
accumulate before disintegrate cell fragments and synthesized fragments eyelids. oil glands of scalp and skin, and glands of eyelids
o May be only epithelial, only connective, or a mix of epithelial, connective, and muscular tissues
o simple columnar epithelia:
linging of GI tract, uterus kidney, and uterine tubes. Nucei oval shaped and stretcher with microvilli. absorption, secretiob, egg
spongy bone
blood, circular piece marrow, dark pieces calcified cartilage red bone marrow. with lighter piece spicules hardened bone matrix (osteocytes w/ lacunae but no rings), line has growing hyaline cartilage
intramembranous ossification
Produces flat bones of skull and clavicle in fetus, Thickens long bones throughout life. between two membranes, embryonic tissue yellowish tan. osteocytes and osteid tissue deposit minerals to deposit tissue and bring blood for bone tissue w/ osteoblasts depositing making matrix and building bone. marrow spaces sticking around w/ calcification building bone stuck w/in own stuff and become osteocytes. osteocytes devleop communicated replacing embryonic mesenchyme w/ bone harter outer layer periosteum outer bone creating diplo bone in between. compact bone osteoblasts push amtrix further out w/ dense matrix further out middle spongy bone and bone marrow caivities. wont have to identify development
other factors affecting bone
At least 20 or more hormones, vitamins, and growth factors affect osseous tissue
Bone growth especially rapid in puberty and adolescence
Estrogen has stronger effect than testosterone on bone growth
Anabolic steroids cause growth to stop
• In muscle cells: changes in voltage result in contraction, shortening of the cel
- Elongated cells that are specialized to contract in response to stimulation
- Primary job is to exert physical force on other tissues and organs
- Creates movements
- Important source of body heat
three types of hair?
lanugo, villus, terminal
organ
structure composed of two or more tissue types that work together to carry out a particular function visibly distinguishable form adjacent features. can be within an organ. hair, nail, gland, nerve and blood vessel is organ within itself
areolar tissue
epithelium- loosely organized, abundant blood vessels, emtype space. random directions of collagen, elastic and reticular presnt skin and mucous membranes. surrounds blood vessels, nerves, muscle, tendon, epithelium rest on leukocytes travel freely
areolar or dense irregular. large space areolar, thicker budnles little space dense irregular.
fibrosis
replacement of damaged cells with scar tissue composed of collagen by fibroblasts doesn’t return function
sweat
Sweat—begins as a protein-free filtrate of blood plasma produced by deep secretory portion of gland
Some sodium chloride and other small solutes remain in the sweat
Some drugs are excreted in sweat
On average, 99% water, with pH range of 4 to 6
Insensible perspiration—500 mL/day
Diaphoresis—sweating with wetness of the skin
2 types: Apocrine and Merocrine/Eccrine
what are the kinds of muscular tissue?
specialized to contract when stimulated and exert physical force on other tissues, organs, or fluid. include: skeletal (multiple nuclei adjacent to plasma membrane, striated [light and dark regions] and voluntary), cardiac (shorter cells cardiomiacities branched or notched at ends only one nucleus light stained region glycogen w/ end junctions of intercalated discs), and smooth (lacks striations, myocytes fusiform and short one central nucleus visceral muscle
ddermal papilla
vascular region hair w/ sole source of nutrition
boundary between epidermis and dermis
boundary between epidermis and dermis is usually wavey fingerlike expenstions of dermal papillae and downward epidermal of papillae are epidermal ridges interlocking in arrangement resist slipping.
Squamous cell carcinoma
Arises from keratinocytes of stratum spinosum. raised reddened scaly appearance
metasistize in lymphnodes then spread, chance of receovery good if not spread
Lesions usually on scalp, ears, lower lip, or back of the hand
Have raised, reddened, scaly appearance later forming a concave ulcer
Chance of recovery good with early detection and surgical removal
Tends to metastasize to lymph nodes and may become lethal
What are fibroblasts?
- make fiber produce brown substance, macrophages- attack foreign material and start immune system from monocytes, leukocytes- white blood cells neutrophils (attack bacteria), lymphocytes (mark antigen), plasma (lymphocytes will turn into when foreign antigens), mast (blood clots heparin inhibit clotting and histamine increases blood flow), adipocytes ( store fat molecules)
bone-
Bone (osseous) tissue is a calcified connective tissue.
osseous tissue, hard calcified connective tissue composes skeleton. bones consist of osseous tissue, cartilage, bone marrow, dense irregular connective tissue. intervertebral discs pads of shock-absorbing cartilage in knee joints. resists compression and absorbs shock in some joints between dense and hyaline. compact bone physical support for body, leverage of muscle action, protective viscera, reservoir calcium
Feedback mechanism
- Negative feedback allows for dynamic equilibrium within a limited range around a set point
- Loss of homeostatic control causes illness or death
- Because feedback mechanisms alter the original changes that triggered them, they are called feedback loops. negative and positive homeostasis. cold vessesl and vasculature constrict, vasodilation causes sweating opening up and becoming bigger goal to bring back set point in middle.
- Person gets up from bed, blood drains from upper body creating homeostatic imablnace, barorectpros above heart respond to drop in blood pressure, send signals to cardiac center of brainstem, cardiac center accelerates heartbeat.
things present in connective tissue?
Fibers Collagenous Reticular Elastic Ground Substance Glycosaminoglycans (GAGs) Proteoglycans Adhesive glycoproteins
burns
UVA and UVB are improperly called “tanning rays” and “burning rays”
Sunscreens protect you from sunburn but unsure if they provide protection against cancer
Burns—leading cause of accidental death
Classified according to depth of tissue involvement
what are two skin pigments?
eumelanin-brownish black, pheomelanin-reddish yellow sulfur.
nerve and muscle tissue
- Nerves and musclse tissue- muscle cell contraction shortening of muscle
- Excitability—ability to respond to stimuli by changing membrane potential based on
- Membrane potential—electrical charge difference (voltage) that occurs across the cell membraneA
osseous titssue
Osseous Tissue: A mature bone remains a metabolically active organ
Involved in its own maintenance of growth and remodeling
Exerts a profound influence over the rest of the body by exchanging minerals with tissue fluid.
builds and shapes itself so it doesnt snap under specific forces load of body on head and forces placed spread throughout bone shift along medial aspect of bone.
lighter skinned people
Lighter skinned people
Melanin clumped near keratinocyte nucleus less color
Little melanin seen beyond stratum basale
breaks down more rapidly so not seen beyond stratum basale.
stratum spinosum
keratinocytes, desmosomes spiny look (keep cells from pulling apart and resist mechanical stress), several layers of keratinocytes thickest. appear flatter w/ dendritic cells bound to eachother by tight function.
terminal
longer, coarser, and more heavily pigmented. eyelashes, eyebrows, and scalp axillary and pubic hair
osteocyte
Former osteoblasts that have become trapped in the matrix they deposited (reside in lacunae, interconnected by canaliculi-lines). contact both other bone cells. resorb bone matrix other deposit. bone remodeling from bone-dissolving osteaclasts and depositing osteoblasts.
Communication- spiderlike projections connecting longer vertical lines and cell bodies
Strain stressors- flow in extracellular fluid of lacunae and canaliculi sensory cilia for bone remodeling. tell osteoblasts to build more bone or osteoclasts to resorp
Matrix of osseous tissue is, by dry weight, about one-third organic and two-thirds inorganic matter
dense regular connective tissue
tendons and bone connecting to moving things allow for stretch so tissues can move and not snap. Tendons attach muscles to bones and ligaments hold bones together
collagen fibers close packed, little space, and parallel to eachother. tendons and ligaments allows for pullingof skeletal fibroblasts few bood vessels.
woody look long collagen fibers nuclei to fibroblasts flattened and running in same direction shortened)
Malignant melanoma
Skin cancer that arises from melanocytes
Less than 5% of skin cancers, but most deadly form
Can be successfully removed if caught early, but if it metastasizes it is usually fatal
Greatest risk factor: familial history of malignant melanoma
Highest incidence in men, redheads, and people who had severe sunburn as a child
What is pelvic?
extends inferiorily to brim of pelvis and is continuos with abdominal cavity but narrows and tilts posteriosrly containing excretory
medulla
loosely arranged collection of cells and air spaces core of loosely arranged cells and air spaces. thick hairs prominent, narrow in median, absent in thin
intraperitoneal
encirculed by peritoneum and connected to posterior body wall
mineralization or calcification
the hardening process of bone Individual bones (organs) consist of bone tissue, bone marrow, cartilage, adipose tissue, nervous tissue, and fibrous connective tissue
hair?
Slender filament of keratinized cells growing from a tube in the skin called a hair follicle. compacted hard keratin, cross-linkages between different keratin molecules making light or denser (cross-linkages)
(pilus keratinized cells that grows from oblique tube hair follice, all have similar density just texture and pigmentation
We lose about 50-100 hairs daily
Hair growth—scalp hairs grow 1 mm per 3 days
functions of connective tissue
ighly variable vascularity • Functions o Support o Connect o Protect
telogen
resting stage. papilla reachs bylb 1-3 months. papilla reaches bulge. catagen or telogen hair may be pushed out.
types of loose connective tissue
- Areolar
* Reticular
nutrient foramina
blood vessels penetrate into bone through minute holes
effector
cell or organ that carries out the final corrective action to restore homeostasis
What is the self amplifying cycle
• Person gets up from bed, blood drains from upper body creating homeostatic imablnace, barorectpros above heart respond to drop in blood pressure, send signals to cardiac center of brainstem, cardiac center accelerates heartbeat.
holism
emergent properties of the whole organism cannot be predicted from the properties of the separate parts. humans are more than sum of part
organic matter in bones
synthesized by osteblasts includes Collagen, carbohydrate–protein complexes, such as glycosaminoglycans, proteoglycans, and glycoproteins
Inorganic matter
85% hydroxyapatite most inorganic
10% calcium carbonate
Other minerals
Bone is a composite material—a combination of a ceramic (hydroxyapatite) support weight w/out sagging and a polymer (collagen) w/ sacrificial bonds that break under stress protecting bone from fracture by dissipating shock..
vellus
fine, pale hair that replaces lanugo by time of birth./ 2/3 of hair of women 1/10 of men, all hair of children.
fractures and their repair
Stress fracture Pathological fracture Fractures classified by structural characteristics Direction of fracture line Break in the skin Multiple pieces
wolff’s law of bone
Wolff’s law of bone: architecture of bone determined by mechanical stresses placed on it w/ bone adapting to withstand stresses devleoping along lines of stress placed on it
Remodeling is a collaborative and precise action of osteoblasts and osteoclasts
Bony processes grow larger in response to mechanical stress
senile atrophy
through normal aging
mixed glands
• Contain both serous and mucous cell types and produce a mixture of the two types of secretions
• homeostasis
the ability to detect change, activate mechanisms that oppose it, and thereby maintain relatively stable internal condition
collagenous connective tissue
collagen, tough and flexible, resist stretcher. 25% of protein, gelatin, leather and glue, white fibers. section coarse wavy bundles making up tendons, ligaments and dermis of skin
integrating control center
control center that proesses the sensory information makes a decision and directs reposne
catagen
degeneration stage- mitosis stops, base of hair keratinizs dark clump. 2-3 weeks. mitsosis in hair matrix ceases and sheath cells below bulge die. follicle shrink and dermal papilla draws up toward bulg. base of hair keratinizes into hard club hair.
osteoclasts
Bone-dissolving cells found on bone surface.
Develop from same bone marrow stem cells that give rise to blood cells (different origin from other bone cells). found on bone surface
Very large cells formed from fusion of several stem cells osteocytes, 3-4 nuclei side facing bone has ruffled border enhancing efficiency of boen resportion.
yellow marrow
found in adults
Fatty marrow that does not produce blood
Can transform back to red marrow in the event of chronic anemia
o simple cuboidal epithelia
liver, thyroid, mammary and salivary glands, bronchioles, and kidney tubules. perfectly round nuclei, ansor[tion and secretion and mucous
o simple squamous epithelia
: located in alveoli, glomeruli, endothelium, and serosa. secretes serous. squished nucleus rapid diffusion and secretion
treatment of fractures
Closed reduction
Open reduction
Cast
mineral deposition
Mineral deposition (mineralization): process in which calcium, phosphate, and other ions are taken from blood and deposited in bone. Osteoblasts lay down collagen fibers in helical pattern along osteon encursten and hardenmatrix w/ crystals
fibrocartilage
move very little discs in back and knee. Chondrocttes paxke din long lines and thick bundles of collagen fibers. Locations: pubic symphysis, menisci, and intervertebral discs
straight noy swuiggly background lighter no elastic
texture
related to cross-sectional shape of hair. straight, wavy, and curly dependent on shape (straight-round, wavy-oval, curly-straight)
cryogenic glands
• Release whole cells (sperm and egg cells)
dense irregular connective tissue
deeper layers of skin and organs move alll different directions bundles and can move any which way unorganized thicker weird bundles of collagen and gland, fibroblasts and spread out, not visible cellsthick bundles of collagen, litte room for cells and ground substance, random unpredictable stress protective capsule
lanugo
fine, downy, unpigmented hair that appears on the fetus in the last 3 months of development
• Four types of cells:
epithelium, connective, nervous, muscle function from cells and how arraned
mucous glands
ral and nasal cavities. Produce glycoprotein, mucin, which absorbs water to form mucus. glycoproteins absorb, goblet cells unicellular
graft options
Autograft: tissue taken from another location on the same person’s body
Split-skin graft—taking epidermis and part of the dermis from an undamaged area such as the thigh or buttocks and grafting it into the burned area
Isograft: skin from identical twin
Five epidermal cell types
Stem cells- undifferentiated cells divide and give rise to keratinocytes in stratum basale
Keratinocytes- majority of epidermal cells. named for role in synthesizing keratin.
Melanocytes- synthesize melanin shield from UV light. stratum basale shed edges of melanin to tip and shield cell from sun
Tactile cells/Merkel cells- touch receptor cells w/ dermal nerve fibers- basal layer associated w/ dermal nerve.
Dendritic cells/Langerhans cells- stratum spinosum and stratum grandulosum, immune cells guard against toxins, microbes, and panthogens.
epithelium function
o functions: protect (barrier to infection, deeper from acid and enzymes skin and stomach), secrete (mucus, sweat, enzymes, hormones, glands), produce, excrete waste (CO2, bile lungs and blood and digestive), absorb (nutrient small intestine), filter (waste blood vessels and kidney, sense (stimuli)
red marrow
(myeloid tissue)
Contains hemopoietic tissue—produces blood cells lymphatic organ
In nearly every bone in a child
In adults, found in skull, vertebrae, ribs, sternum, part of pelvic girdle, and proximal heads of humerus and femur
cortical bone
on outside of bone
integumentary system?
Consists of the skin and accessory organs; hair, nails, and cutaneous glands. most vulnerable of body and more medical treatment than any other par
elastic cartilage
conspicuous elastic fibers makes ECM more noticeable. weblike mesh and lacunae, covered by perichondreium, external ear epiglottis, provides flexible organic support . areas that move epiglottis. Biggerchrondroctres by wavy lines elastic fibers. Locations: external ear and epiglottis
What is visceral?
covers organ surface, parietal lines inside of body cavity
infarction
sudden death of tissue when blood supply is cut off
mineral resorption
Mineral resorption: process of dissolving bone and releasing minerals into blood osteoclasts border ruflfed. hydrogen pumps for space between osteoclasts. hydrochloric acid dissolves bone, acid proteast digests collagen. Orthodontic appliances (braces) reposition teeth through resorption and deposit
hair and nails are…
Hair, nails, and cutaneous glands are accessory organs (appendages) of the skin. Hair and nails are composed of mostly dead, keratinized cells
stratum corneum is soft kerain, hair and nails are hard keratin
Fingernails and toenails—clear, hard derivatives of stratum corneum. very thin, dead scally cells densely packed together and filled w/ parallel fibers of hard keratin.
three types of skin cancer
Three types of skin cancer named for the epidermal cells in which they originate.
basal, squamous, malignant
common in fair skin and oldest individuals. head neck and hands, highest survivial rate
endochondral ossification
endochonral ossification- mesnsechym develops into hyaline cartilage model down first bone cells.
cartilage transitions to bone elongating it
Fibrous perichondrium covers and produces chondrocytes w/ cartilage growing. secondary centers of ossification w/ epiphyses cartilage between those stick around Chondrocytes inflate and die, thin walls calfiy. perichondrium produces, perichondreum to periosteum produce osteoblast depoist thin collar of bone cartilage model, reinforcing chondrocytes lacunae merge into single cavity. osteoclasts eat away at cartilage hollwoing out. develop osteoblast secrete minerals build bones replace cartilage model w/ bone cartilage dies and osteoclasts die.
stratum corneum
can have 30 dead cells barrier against outside work resisting penetration and water loss. resistant to abrasion, penetration, and water loss. causes wrinkling when to much water is absorbed
bone remodeling
Absorption and deposition
Occurs throughout life—10% of skeleton per year
Repairs microfractures, releases minerals into blood, reshapes bones in response to use and disuse
exocrine
ducts connected to surface, external or internal (pancreas and salivary) ducts pancreas or salivary (liver pancreas and gonads have both). Maintain their contact with surface of epithelium by way of a duct
maintain contact w/ surface via septum then duct convey secretion to surface
unicellular
epithelial, nonsecretary exocrine or endocrine Unicellular glands—found in an epithelium that is predominantly nonsecretory. Can be exocrine or endocrine
secretory cells in epithelium nonsecretory endocrine (digestive) or exocrine (respirator)
endothelium
circulatory system lined with simple squamous rests on thin layer of areolar tissue, resting on elastic sheet make up a tunica interna (blood vessels) and endocardium of heart
chemicals
concentration gradient, charged particles electrical gradients, and heat with thermal gradients
hair follicle & matrix
Hair Follicle Consists of: Dermal papilla
Hair matrix- hair’s growth center all high up are dead.
parathyroid hormone
secreted by parathyroid glands on posterior surface of thyroid
PTH released when calcium levels low in blood. stimulates osteoblasts to secrete increasing bone resorption. promotes calcium resorption by kidneys less lost in kidneys. calciltriol increase in kidney. inhbiitng collagen synthesis to osteoblasts
PTH raises calcium blood level by four mechanisms
endocrine
no ducts use blood
lose contact w/ surface w/ no ducts but high density blood capilarries w/ hormones directly into blood.
follicle
Extends into dermis and possibly hypodermis
Epithelial root sheath- extension of epidermis conssits of stratified squamous epithelium and lies immediately adjacent to hair root.
Connective tissue root sheath
diagonal tube contains hair root
bulge- deep end of follicle, source of stem cells for follicle growth. connective root sheath derived from dermis and composed of collagenous connective tissue surrounding epithelial sheath and somewhat denser than adjacent dermis
muscle types
o Skeletal
o Cardiac
o Smooth
cardiac
heart, branches shorter than skeletal, beaches off not parallel like tree, striations along, intercalculated discs (dark pink lines communications and signals between branching) where connecting is the disc, cells with nuclei stretches but centralized
(dark pink lines communications and signals between branching intercalated discs, places where long tubes have branches that interconnect)
hypodermis
below dermis subcutaneous not part of skin. indistinct difference but more areolar and adipose tissue, padding body and binds skin to underlying tissue.
blood
• Blood: fluid connective tissue, transport cells and dissolved Magger from place to place. Platelets (little red/purple lines), erythrocytes (red blood cells pale centers no nuclei, leukocytes (white blood cells defense larger variously shaped nuclei, larger purple mesh)
bone cells
osteogenic, osteoblast, osteoclast, osteocyte
epithelium
avascular no blood vessel lie on vessel rich connective tissue
o epithelial are sheets of closely adhering cells, one or more cells thick
o covers body surface and lines body cavities. generally exposed to environment or other side of organs, nourshied by underlying tissue glands and ducts
o cells are very close together, high rate of mitosis, parts of cell: basement memberane, basal surface (line of dark purple cells) , apical surface (away) sitting on connective tissue near basal membrane (collagen, glycoprotein, protein-carbohydrate complexes acts as anchor binds growth factor dictate devlopment
skin has five types of glands
merocrine sweat glands, apocrine sweat glands, sebaceous glands, ceruminous glands, and mammary glands
sudoriferous glands- of two kinds: apocrine and merocrine
receptor
structure that senses change in body
bone marrow
soft tissue occupying marrow cavities of long bones and small spaces of spongy bone and larger central cnaals.
skin functions
Sensation- react to heat, cold, touch, texture, pressure, vibration, and tissue injury found on face, palms, fingers, soles, nipples and genitals.
Heat regulation- 10X as much blood flow, nerve endings monitor body surface temp. body retains heat by constricting blood vessels of dermis, keeping warm blood deeper in body loses excess by dilating vesicles. sweat glands secrete perspiration.
Absorption
Protection- trauama and infection w/ keratin and desmosomes, from excess water and barrier to UV
Excretion- waste from kidneys, body odor
Secretion- sweat, pheromones
retroperitoneal
lie against posterior body wall and covered by peritneum only on side facing cavity (kidneys, uretrs, adrenal glands, pancreas, aorta and inferior vena cava.
cuticle
layers of thin scaly cells. multiple layers of very thin, scaly cells that overlap each other interlock resist pulling onhair.
stratified squamous
o Most widespread epithelium in the body
o Deepest layers undergo continuous mitosis
o Two kinds of stratified squamous epithelia
o Keratinized
o Nonkeratinized