unit 2 Flashcards
epidermis + dermis
cutaneous membrane
hair follicles, nails, exocrine glands
accessory structures
cutaneous + accessory structure
integumentary systems
- resistance to trauma + infection – keratin, desmosomes
- other barrier functions (water, UV, chemicals)
- vitamin d synthesis
- sensation
- thermoregulation
- nonverbal communication
major functions of the skin
provide sensation
receptors
- vitamin d enters body from diet or synthesis in skin
- vitamin d chemically modified first by the live and then bye he kidneys to function
- active vit d increase absorption of ca + phosphorus in intestine
- active vit d also increases bone breakdown which releases ca + phosphorus into blood; at kidneys, ca retention is stimulated reducing the amt lost in the urine
- normal levels of blood ca and phosphorus support mineralization of the bone
vitamin d synthesis
______ associated with sensory neurons whose endings (dendrites) function as receptors
sensation
- keratinocytes
- stem cells
- melanocytes
- tactile cells.
- dendritic cells
Epidermis cells
“Kinky Strippers Make Terrible Dancers”epidermis cells
what are the epidermis cells?
mnemonic – “Kinky Strippers Make Terrible Dancers”
- keratinocytes
- stem cells
- melanocytes
- tactile cells.
- dendritic cells
_____ is a major determinant of skin coloration
melanin
what are the two melanin types
eumelanin + phaeomelanin
______ produce melanin in mealnosomes
melanocytes
______ are transferred to keratinocytes
melanosomes
t/f individuals produce diff numbers of melanocytes
FALSE; THEY PRODUCE SIMILAR AMTS
- pigment molecules: melanin (phaeomelanin + eumelanin), karaten
- blood flow (more = redness, less = pallor “pale”)
- oxygenation of blood (cyanosis = little blood)
- other: bruising, liver tissues. dark hyperpigmentation cause by insulin resistance + elevated blood glucose, inflammation
skin color influenced by other factors than melanin
stratified keratinized squamous epithelium
epidermis
dead keratinized cells of the skin surface
stratum corneum
clear, featureless, narrow zone seen only in thick skin
stratum lucidum
2-5 layers o cells with dark staining keratohyalin granules; scanty in thin skin
stratum grandulosum
- many layers of keratinocytes, typically shrunken in sized tussles but attached to each other by desmosomes, which give them spiny look
- progressively fleeted the father they are away from dermis
- dendritic cells are abundant here but are not distinguishable in routinely stained preparations
stratum spinosum
- sijnjgle layer of cuboidal to columnar cells resting on basement membrane
- site of most mitosis
- consists of stem cells,keratinocytes, melanocytes, tactile cells, but these are difficult to distinguish the routine stains
- melanin is conspicuous in keratinocytes of this layer in black and brown skin
stratum basale
fibrous connective tissue; richly endowed with blood vessels + nerve endings
- sweat glands + hair follicles originate here and in hypodermic
dermis
superficial 1/5 of debris
- composed of areolar tissue
- often extend upward as dermal papillae
papillary layer
deeper 4/5th of dermis
- dense irregular connective tissue
reticular layer
which layer of the epidermis skin is only present in thick skin
stratum lucidum
Many vessels, receptors, and accessory structures (accessory organs) are associated with the ____
dermis
Functions of hair:
1. Provide sensation – bending of hairs stimulate root hair plexus (hair receptor)
2. Enhance facial expression (eyebrows)
3. Protection * Insects
* Foreign particles
* UV light, trauma, heat loss (head only)
A hair (pilus) is produced by a hair follicle
is comprised of keratinized epithelial cells (hard keratin
instead of soft keratin)
* Hairmedulla
* Haircortex
* Hair cuticle
Hair follicle consists of an epithelial root sheath and a connective tissue root sheath
hair
protect tips of fingers and toes, aid in sensitivity to small objects
Like hairs, comprised of thin dead cells and hard keratin
Nails
Glands that produce perspiration
Sweat glands
Sweat glands that function in evaporative cooling; widely distributed over the body surface; open by ducts onto the skin surface
Eccrine glands
Sweat glands that function as scent glands; found in the regions covered by the pubic, axillary, and male facial hair; open by ducts into hair follicles
Apocrine glands
Oil glands associated with hair follicles
Sebaceous glands
Glands of the ear canal that contribute to the cerumen (earwax)
Ceruminous glands
Milk-producing glands located in the breasts
Mammary glands
Sebaceous glands are exocrine glands that produce ___ and release it by holocrine secretion
sebum
mix triglycerides, cholesterol, proteins, electrolytes
sebum
- inhibits growth bacteria
- Lubricates + protects hair shaft
- Conditions the skin
functions of the skin
raise hairs and push sebum towards the lumen of the hair follicle/surface of the skin
arrector pili muscles
Sweat + fatty substances + proteins; viscous, milky or yellowish
Sweat; 99% water, salts, vitamin c, antibodies, dermcidin (microbe-killing peptide), metabolic wastes
secretion
Odorless until bacterial interaction –> body odor
- thermoregulation
- excretion
- protection from environmental hazards
functions of eccrine sweat glands
- Produce a secretion that mixes with sebum to form cerumen (earwax)
- prevents foreign particles from reaching the eardrum
- keeps eardrum pliable and waterproofs ear canal,
Ceruminous glands (modified apocrine glands)
Some anti-acne medications work by reducing sebum production. Why would dry skin be a side effect of this?
Dry skin is a side effect of anti-acne medications that reduce sebum production because sebum naturally moisturizes and protects the skin. Without adequate sebum, the skin loses moisture, leading to dryness and irritation.
Anhidrosis (also called hypohydrosis) is a condition in which the sweat glands do not function as they should (i.e., make too little sweat). Why might this be dangerous, even life threatening to a person on a hot summer’s day?
Anhidrosis can be dangerous because sweating is essential for cooling the body down and regulating temperature. Without adequate sweat production, the body can overheat, leading to heat exhaustion or potentially life-threatening heatstroke.
- support
- protection
- movement: force of muscles transferred to skeleton to create movement
- electrolyte balance : storage of ca + phosphate
- acid-base balance — phosphate and carbonate salts
- blood formation : red bone marrow produces the formed elements
- hormone secretion: osteocalcin helps regulate blood glucose and fat deposition
functions of the skeleton
____bones are often slightly curved, have two parallel flattened surfaces
flat
Short versus long is about proportions (length vs width), NOT overall size T/F
T
______ bones form in tendons, vary in size and numbers
Sesamoid
- projections
- articulating with other bones
- openings and depressions
bone marking/features
____ tissue is harden by the deposition of ca phosphate salts (process = mineralization/calcification)
osseous
compact bone is aka?
cortical bone
spongy bone is aka?
cancellous bone
spaces within spongy bone are filled with ____
bone marrow (red/yellow)
externally bones are covered with connective tissue sheath Called _____
periosteum
cellular layer
osteogenic
- fibrous
- cellular layer
- supports a nerve and blood vessel supply
- anchoring and attachment of tendons and ligaments
- osteogenic layer is important for bone remodeling, growth, + fracture repair
periosteum
_____ layer is important for bone remodeling, growth, + fracture repair
osteogenic
_____ fibers strengthen the periosteum’s attachment to bone
perforating
______ fibers of periosteum penetrate the bone tissue
collagen
insides of bones are covered by ______
endosteum
- reticular connective tissue + cells (osteoblasts, osteoprogenitor cells)
- similar functions to cellular layer of periosteum
- lines internal marrow cavity, surfaces of spongy bone, and canal system of bones
endosteum
- diaphysis (shaft)
- epiphysis (expanded ends)
- epiphyseal lines are remnants of the growth plates
- metaphysics (flared part btw the epiphysis & diaphysis
- ends of long bones are covered in articular cartilage
- periosteum + endosteum
- medullary cavity
- articular cartilage
gross anatomy of long bones
- ends of long bones are covered in _____ _____
articular cartilage
what are the major vessels that supply the long bones
nutrient artery + vein
- Thin Sheets of spongy bone sandwiched btw compact bone
- has both periosteum and endosteum
- consist of lattice of delicate silvers called spicules(rods or spines) + trabeculae (thin plates or beams)
gross anatomy of flat bones
- osteogenic
- osteoblasts
- osteoclasts
- osteocytes
histology of osseous tissues
initially build osteoid and calcification transforms osteoid to bone
osteoblasts
found in lacunae, connected by canaliculi
osteocytes
breaks down matrix
osteoclasts
production of new bone matrix
osteogenesis or ossification
- secrete unmineralized matrix (osteoid) that includes collagen + calcium binding proteins
- release alkaline phosphatase, which makes inorganic phosphate available —
allows calcium phosphate salts to form
osteoblasts
- osteoblasts become ____ (trapped in matrix after it hardens)
- canaliculi contain extensions of ___ cytoplasm + membrane
- osteocytes connected to one another by gap junctions
osteocyte
breaking down of bone
osteolysis or resorption
what does Ca salts add to bones
hardness
ca salts has little resistance to
tension (pulling + twisting)
collagen fibers adds what to bones
resisting pulling and twisting forces
collagen fibers on its own has little resistance to ___
compression
functional unit of compact bone
osteon
“little plates”, layers of matrix
lamellae
Haversian canal; blood vessels and nerves
central canal
- central canal vs perforating canal
- osteons
- other lamellae
Compact bone structure
spicules(delicate rods or spines) + trabeculae (thin plates or beams)
- trabeculae arranged along stress lines
spongy bone
- lamellae are irregularly arranged, only have few cell layers, so central canals aren’t needed
- canaliculi open onto surface, nutrients come from capillaries associated with the endosteum
organization of lamellae in spongy bone
- red marrow vs yellow (adipose)
bone marrow
___ bone most abundant where bone is not heavily stressed or stresses originate from many directions
spongy
_____ can also help transfer forces — oriented along lines of mechanical stress
trabeculae
___ bones thickest where forces applied from limited number of directions
compact
embryonic skeleton starts as ____ connective tissue membranes & ____ cartilage
fibrous; hyaline
- most complex means of bone formation b/c cartilage must be broken down as ossification proceeds
endochondral ossification
ossification = process of bone tissue formation
osteogenesis
deposition of calcium salts
calcification
_____ are areas of hyaline cartilage that allow long bones to elongate until ossify
epiphyseal
- expand within to increase in length
- division of chondrocytes of the epiphyseal cartilage
- bone replaces cartilage at roughly the same rate cartilage grows
interstitial growth
- new matrix secreted against an external face of an existing boundary
- increase in width – thickens + strengthens long bone by adding layers of circumferential lamellae to outside
- involves periosteum + endosteum
- associated with increasing the thickness of bones, enlargement of the medullary cavity
appositional growth
architecture of bone is deterred by mechanical stressed placed upon it
Wolff’s law of bone
______ lie along stress lines
trabeculae
- involves osteocytes, osteoblasts, and osteoclasts
- recycle + renew bone matrix
- contributes to calcium homeostasis
bone remodeling
loss bone density
osteopenia
advances loss of bone density where bone fractures easily, spinal deformities common due to weight o upper body can collapse vertebrae
osteoporosis
- severe neuromuscular problems
- hyperexcitability (levels too low)
hypocalcemia
- nonresponsive (levels too high)
- deposits of calcium salts in blood vessels, kidneys can interfere with function
hypercalcemia
homeostatic mechanism regulate calcium storage, absorption, and exertion ; involving ____ feedback
negative
adapt stress – heavily stressed bones become thicker + stronger by stimulating _____
osteoblasts
require for collagen synthesis
vit c
stimulates osteoblast activity
vit a
required for synthesis of bone proteins
vit k + b12
what hormones stimulate bone growth
growth + thyroxine
estrogen and testosterone stimulate osteoblasts
sex hormones
maintains calcium ion and homeostasis
parathyroid + calcitonin
- excitable
- conductivity: local electrical excitation sets off a wave of excitation
- contractibility
- extensibility
- elasticity
universal characteristics of muscles
- produce movement
- maintain posture and body position, support
- control of body openings + passages
- maintain body temperature – produce heart
- store nutrients
- glycemic control: absorb, store, + use sugar; secrete hormones (myokines) that affect liver activity + fat breakdown
skeletal muscle
muscle cells with elongated shapes
muscle fibers
complete organ surrounded by muscular fascia + epimysium; had m any blood vessels + nerves, including motor neurons that stimulate contraction
whole muscle
bundle of muscle fibers within the entire muscle; surrounded but he connective tissue layer, perimysium
muscle fascicle
individual muscle cell with a disciple; surrounded but he connective tissue layer, endomysium
muscle fiber
groups of contractile protein within individual fibers; surrounded red by specialized endoplasmic reticulum called sarcoplasmic reticulum
myofibril
protein filaments, either myosin or actin; interact to shorten the muscle fiber during contraction
myofilament
provide routes for blood vessels and nerves to enter the muscle, stabilize their positions
connection tissue sheaths
sheet of connective tussle that separates neighboring muscles or groups from each other or subcutaneous tissue
fascia
dense irregular connective tissue
epimysium
surrounds disciples (bundles of 2-60 fibers)
perimysium
delicate, loose connective tussle sheath, chemical environment is important for muscle function
endomysium
each nucleus in skeletal muscle corresponds to one ___
myoblast
spindle shaped precursors to muscle cells that fuse together to form long cylindrical cells
- repair is possible because some myoblasts remain as adult stem cells called statellite cells
myoblasts
mature fibers are filled with actin and myosin proteins – regulated arrangement gives ____ pattern
striated
plasma mem
sacrolemma
cytoplasm
sarcoplasm
long protein cords
myofibrils
aerobic cellular respiration
mitochondria
transverse tubule + terminal cistern of sarcoplasmic reticulum
triads
myofibrils are ___ during contraction
shortened
A band
dArk
I band
lIght
Thin filaments are associated with ____
actin (more light shines through)
Thick filaments are associated with ____
myosin(less light shines through)
elastic filament (titin) attach thick filaments to ___ line and facilities recoil to resting length to avoid overstretching
z
actin + myosin are considered ____ proteins
contractile
tropomyosin + troponin are considered ___ proteins
regulatory
links actin to the sacrolemma – ultimately helps transfer the endomysium + and ultimately the tendon
dystrophin
- H bands & I bands narrow, ones of overlap widen
- z lines move closer together
- width of A band remains constant
during contraction
how do we get contraction of all the sarcomeres within a muscle fiber at once
excitation-contraction coupling
protein anions are outside or inside the cell more
inside
skeletal muscles only contract when they receive signals from ___ neurons
motor
which NT is involved in muscle contraction
ACH
area where the signals are received
motor endplate
space that separates axon terminal from the motor endplate
synaptic cleft
postsynaptic membranes folds increase the surface area for ___
receptors
ACH binds ligand gated channels –> ?
end plate potential (mem potential at the motor endplate becomes less neg)
voltage gated channels will propagate the action potentials along the sarcolemma and down the ?
transverse tubules
voltage sensitive tubule proteins of T tubules change shape, which opens __ ion channels in terminal cisterns of the sarcoplasmic reticulum
calcium
acetylcholinesterase breaks down _____ –> ligand-gated channels close
acetylcholine
calcium is taken back into the sarcoplasmic reticulum
- troponin will return to it s original shape / position
- moves tropomyosin back to origin position
- active sites covered
- cross-bridges unable to form
- contraction ends
muscle relaxation
- length of sarcomere at the start of contraction
- frequency of the stimulus
- which motor units are contracting
- total number of motor units contracting (recruitment)
what affects the amount of tension produced
- action potential propagates along sarcolemma and down t tubules
- calcium ions are released from the sarcoplasmic reticulum
- ca binds to troponin
- troponin gets moved
- ## active sites exposed thick and thin filaments
muscle contraction
