midterm Flashcards
negative feedback loop examples
- blood sugar rises, insulin brings down
- vasodilation and vasoconstriction
positive feedback loop examples
- birthing contractions
epithelial tissue
body surfaces, hollow organs, glands
connective tissues
binds organs together, energy reserves for fat
muscle tissues
movement and force
nervous tissue
stimulates action potential body functions
simple squamous epithelium
filtration, diffusion, osmosis, secretion
kidney, lungs, heart & blood vessels
simple cuboidal epithelium
secretion, absorption
kidney tubes, ovary surface
simple columnar epithelium
moves fluids and particles along passageways
respiratory tract, Fallopian tubes, sinuses
stratified squamous epithelium
stratified = 2+ layer
many layers of flat cells
skin & mouth
stratified cuboidal epithelium
2 layers of cube shaped cells
glands
stratified columnar epithelium
(rare) layers of column like cells
throat, male urethra
pseudostratified epithelium
seems like multiple layer b/c mixed cells, but actually 1 layer
muscle secretion & movement
respiratory tract
skeletal muscle
attached to bones or facial muscles
shape: single, long, cylindrical, straited
components: epimysium, perimysium, endomysium
regulation: voluntary
speed: slow -> fast
rhythmic: no
cardiac muscle
walls of the heart
shape: branching chains of cells, striations + discs
components: endomysium, attached to fibrous skeleton of heart
regulation: involuntary
speed: slow
rhythmic: yes
smooth muscle
walls of hollow organs other than heart
shape: single, no striations (egg thing)
components: endomysium
regulation: involuntary
speed: very slow
rhythmic: yes, for some
simple diffusion
diffusion w/o transport proteins or ATP (like oxygen)
facilitated diffusion
passage across membrane through transport protein
osmosis
diffusion of water molecules across selectively permeable membranes
isotonic
equal
hypotonic
higher concentration of solvent than solute, wants to enter bc theres more outside
BLOW
hypertonic
lower concentration of solvent than solute, wants to exit because theres more inside
SHRIVEL
eukaryotic vs prokaryotic
eukayrotic = human, animal
prokaryotic = bacteria
blood plasma typical solute concentration
0.9%
keratinocytes
90%
produce keratin
langerhan cells
@ bone marrow
assist in immune response
fibroblast cells
produce collagen
merkell cells
@ deepest layer
detect touch stimuli and transmits it to sensory nerves
melanocytes
8%
produce melanin
endocrine gland
release hormones directly in bloodstream, no ducts
exocrine
release substance through ducts (sweat, sebaceous)
sudoriferous (sweat) glands
eccrine sweat glands
apocrine sweat glands
eccrine sweat glands
most areas of skin – within dermis, with duct, to surface
apocrine sweat glands
armpit & pubic region, secretions more milky
sebaceous oil glands
sebum: cholesterol, proteins, fat, salts
- keep hair soft and pliable
-inhibits growth of bacteria and fungi
acne:
-bacterial inflammation of gland
wound healing
1) inflammatory phase: clot unites wound edges
2) migratory phase: regrowth of epithelial tissues and fibroblast scar tissue
3) proliferative phase: completion of tissue formation
4) maturation phase: scab falls off
skin cancers
basal cell carcinoma - rarely metastasize
squamous cell carcinoma - may metstarize
malignant melanoma - metastasize rapidly
meisseners corpuscle
found in the dermal papillae, light touch
pacinian corpuscles
deeper layers of skin and other connective tissues like joint capsules - deep pressure
myosin vs actin
myosin : thick filament
actin : thin filament
bundles of muscle fibers
fascicles
contractile unit of muscle cells
sarcomere
cell membrane of muscle cells
sarcolemma
muscle contraction
- In a resting muscle, the protein tropomyosin blocks the active sites on the actin filament, preventing the binding of myosin heads to actin.
- Calcium ions are stored in the sarcoplasmic reticulum (SR), a specialized organelle in muscle cells, and are not freely available in the cytoplasm.
- When a nerve impulse (action potential) reaches the muscle fiber, it is transmitted along the sarcolemma (muscle cell membrane) and down the T-tubules.
- This electrical signal triggers the release of calcium ions from the sarcoplasmic reticulum into the cytoplasm.
- The released calcium ions bind to the troponin protein, which is part of the actin filament complex which reveals binding sites for myosin head to form a cross-bridge.
- Troponin undergoes a conformational change, which moves tropomyosin away from the active binding sites on actin.
- Myosin heads use energy from ATP to pull the actin filaments toward the center of the sarcomere in a process called the power stroke. This shortens the sarcomere and produces muscle contraction.
- When the nerve impulse ends, calcium ions are actively pumped back into the sarcoplasmic reticulum by calcium pumps (using ATP).
- As calcium levels in the cytoplasm decrease, troponin returns to its original shape, allowing tropomyosin to block the actin active sites again. This allows the muscle to relax.
