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32 Cards in this Set

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  • Back
Muscle
three types:
-skeletal, cardiac, smooth

-purposes include:
bodymovement, stabilizing body position, movement of substance through body, generating heat to maintain body temp
skeletal muscle
-voluntary (controlled by somatic system of PNS)
-connects bones by tendons (muscle to bone) or ligaments (bone to bone)

-work in groups where agonist contracts while a second muscle or antagonist stretches and bone moves in opposite directions

-bi's and tri's are antagonistic and also synergistic in that they assist agonist by stabalizing the origin bone or by py positioning the insertion bone during movement.

-contraction can squeeze blood and lymp vessels and aid circulation

-related to leverage concept in physics: most lever systems of body act to increase required force of a muscle contraction, a greater force than mg is required to lift mass m, to reduce bulk of body and increase range of movement

-multinnucleate
sarcomere
-smallest functional unit of skeletal muscle
-composed of thick and thin protein filaments

-positioned end to end to form myofibril
sarcoplasmic reticulum
-specialized ER that surrounds myofybrils in skeletal muscle
-lumen is filled with Ca 2+ ions
sarcolemma
-modified membrane that wraps several myofibrils together
thick filament
-protein filament that makes up sarcomere
-made of myosin
thin filament
-made of actin
5 stage cycle of skeletal muscle contraction
-tropomyosin covers an active site on actin preventing the myosin head from binding

-myosin head remains cocked in high energy position

-in presence of Ca 2+ troponin pulls tropomyosin back exposing active site allowing myosin head tobind to acin

-myosin head expels a phosphate and ADP and bends into a low energy position dragging actin along
(called power stroke because sarcomere shortens and muscle contracts)

-ATP attaches to myosin head causing it to detach from active site which is covered by tropomyosin

-ATP splits into inorganic phosphate and ADP causing myosin to cock in high energy position and cycle repeats to form contraction

-H zone and I band get smaller while A band does not change
neuromuscular synapse
-where neuron attaches to muscle delivering action potential via acetylcholine
T-tubules
-tubes that move deep into muscle spreading Action Potential allowing for uniform contraction

-transfers AP to sarcoplasmic reticulum where Ca2+ becomes permeable

-Ca2+ is actively pumped back into sarcoplasmic reticulum afte end of each cycle
Motor Units
-2-2000 fibers spread throughout the muscle are innervated by a single neuron

-motor units are independent of each other and force of contraction depends on number and size of motor units activated

-smaller motor units are first to be activated and larger units are recruited

-muscles that require intricate movements have smaller motor units where as muscles like the back have large motor units
skeletal muscle fiber type
-slow oxidative (type I)
-fast oxidative (type IIA)
-fast glycotic (type IIB)

-most muscles have mixture of fibers

-ratio of mixtures depends on type of contraction needed

-large amounts of type I found in postural muscles

-Large amounts of type IIA are found in legs

-Large amounts of type IIB are found in upper arms

-cells of muscle do not undergo mitosis bc they are so specialized, instead the fiber can increse in diameter, number of mitochondria increase and sarcomeres lengthen (hypertrophy)
Slow oxidative (type I) skeletal muscle
-type of skeletal muscle fiber
-red
-contain large amounts of myoglobin (similar to hemoglobin but can only carry 1 molecule of oxygen)
-contain larg amounts of mitochondria
-split ATP slowly
-slow to fatigue but have slow contraction velocity
Fast oxidative (type IIA)
-fast twitch muscle fibers
-red
-split ATP at high rate relative to Type I
-contract rapidly relative to type I
-less resistant to fatigue relative to type I
Fast glycotic (type IIB)
-fast twitch fibers
-low myoglobin content
-white
-contract rapidly
-large amounts of glycogen
cardiac muscle
-striated like skeletel muscle meaning it is composed of sarcomeres
-makes up heart
-each muscle has one nucleus as opposed to multinucleus of skeletal muscle
-muscle cell separated from neighbors by intercalated disk which contains gap junctions that allow spread of action potential
-more and bigger mitochondria
-not connected to bone it forms a net which contracts in upon itslef like a squeezing fist
-involuntary (autonomic system)
-depolarization created by slow voltage-gated calcium channels
smooth muscle
-involuntary (autonomic nervous sytem)
-one nucleus just like cardiac muscle
-contain intermediate filaments attached to dense bodies throughout cell

-two types: single unit (visceral)

- multi unit

-contracts or relaxes in presence of hormones orto changes in pH, O2, and CO2, temperature, ion concentrations
single unit smooth muscle (aka visceral)
-connected by gap junctions which allow cells to contract as single unit

-found in small arteries and veins, stomach, intestines, uterus, urinary bladder
multi-unit
-attached directly to a neuron
-can contract independently of other muscle fibers
-found in large arteries, bronchiles, pili muscles attached to hair follicles and iris
Bone
-is living tissue
-support of soft tissue
-protection of internal organs
-assistance in movement
-mineral storage
-blood cell production
-energy storage in the form of adipose cells in marrow
Osteoblasts
-not capable of mitosis
-build bone
Osteocytes
-incapable of mitosis
-exchange nutrients and waste material with blood
Osteoclasts
-resorb bone matrix
-release minerals back into blood
-inhibited by calcitonin
-stimulated by parathyroid hormone
spongy bone
-contain red bone marrow, site of rhemopoiesis or red blood cell development
compact bone
-surrounds medullary cavity
(medullary cavity holds yellow bone marrow)
-highly organized
-where the osteon system occurs
Osteon
-entire system of lamellae and haversian canal

-haversian canal is when osteoclasts burrow haversian tunnels and are followed by osteoblasts which build bone forming rings called lamellae

meanwhile osteocytes trapped between lamellae exchange nutrients via canaliculi

-haversian canals connected by volkmans canal
hydroxyapatite
-how most of Ca 2+ in body is stored
Bone and mineral homeostasis
-bones store calcium and phosphate helping maintain a consistent concentration in the blood
-stores energy
-forms blood cells (spongy bone)
Cartilage
flexible resilient connective tissue composed of collagen
Skin
-an organ
functions in:
-thermoregulation
-piloerection (hairs extend to trap insulating air via sympathetic stimulation)
-protection
-environmental and sensory input
-excretion (water and salts)
-immunity
-hlood reservoir
-vitamin D synthesis (activated when sunlight hits skin)
epidermis
-no blood vessels
-90% composed of keratinocytes which produce keratin, protein that waterproofs skin
-melanocytes transfer melanin (skin pigment)
-langerhans cells interact with helper T-cells
-Merkel cells: attach to sensory neurons in function of touch

-five layers of epidermis
-cells continuously divide to form keratinocytes and are pushed to top layer in process in which they lose organelles and cytoplasm
dermis
connective tissue derived from mesodermal cells
-embedded by blood vessels, nerves, glands and hair follicles
-collagen in dermis provies skin with strength

integumentary system is made up by skin, hair, nails, glands, and nerve endings

-from ectoderm

-below epidermis