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THE MCAT BIO-7

MUSCLE, SKELETAL, AND IMMUNE SYSTEM

QuestionAnswer
What is characteristic of osteoporosis? decreased osteoblas and increased osteoclast activity
Skeletal muscle -striated? -number of nuclei -tire easily? -striated -multiple nuclei -strong but tire easily
Smooth muscle -striated? -number of nuclei -tire easily? -not striated -single nucleus per cell -weak but doesn't tire easily
Cardiac muscle -striated? -number of nuclei -tire easily? -striated -single nucleus per cell -strong and doesn't tire easily
What attaches muscle to bone? tendon
What is a ligament? attaches bone to bone
What are antagonistic / agonistic muscles? -agonist - contracts -antagonist - stretches
What are main functions of muscle contractions? -generate mvmt -aid circulation -produce large amt of heat
sarcomere and what is it made of? -basic fxnal unit of skeletal muscle -thick and thin filaments
myofibril sarcomeres placed end to end
sarcoplasmic reticulum muscle cell ER filled with Ca that surrounds myofibrils
sarcolemma mem that wraps several myofibrils together to form muscle cell
myocyte muscle cell
fasciculus many myofibrils bound together to form a single muscle
What are thick and thin filaments made of? -thick = myosin -thin = actin
Z-line -sarcomere boundary -anchors thin filaments -creates striated look
M-line runs down center of sarcomere
I-band REgion with thin filaments only
H-zone Region with thick filaments only
A-band Contains all the filaments (thick and thin) where they overlap
What does not change during a muscle contraction? A-band
What are 3 stages for contraction? initiation, sarcomere shortening, relaxation
What ntm does nx release to activate muscle? AcH
What are steps from nx to calcium release from Sarcoplasmic Reticulum? nx --> muscle --> sarcolemma --> t-tubules --> SR
What is created to move muscle? Action potential!
t-tubules connected to sarcolemma to allow ions to uniformly flow and runs deep into cx
What two factors are attached to actin during contraction? troponin and tropomyosin
________ covers active site on actin to prevent myosin from binding Tropomyosin
In presence of ______, _____ pulls tropomyosin back to expose active site for myosin. -calcium -troponin
Myosin expels _________ and assumes lower energy position to drag actin with it. phosphate and ADP
What powers the "power stroke"? energy from ATPase activity in myosin head
What does the power stroke create? shoretening of sarcomere
What releases myosin head from actin? ATP
Before contraction, myosin is in _______ state with ________ attached -high energy -phosphate and ADP
Why is calcium impt for muscle contraction? myosin binding site will be covered by tropomyosin
What creates rigor mortis? ATP is no longer produced --> myosin heads cannot detach from actin
Is ATP directly needed for powerstroke? NO --> only needed for detachment of myosin head from actin
When myosin binds with actin, myosin expels ______ and assumes _____ energy position -phosphate and ADP -lower
tetanus contractions become so frequent that muscle has no time to relax --> fatigue
motor unit single motor nx and all corresponding muscle fibers it innervates
Muscles with intricate mvmts have ____ motor units. smaller
Myoglobin stores oxygen inside muscle cx (only one O2)
slow oxidative red fibers (Type 1) and why are they slow? high myoglobin and mitochondria --> split ATP at slow rate and slow to fatigue
Fast oxidative red fibers (Type IIA) and why are they fast? -split ATP at a high rate -not as resistant to fatigue
Hemoglobin binds O2 tighter than myoglobin. FALSE --> myoglobin binds tighter
Fast glycolytic white fibers (Type IIB) -low myoglobin and high glycogen
Do white or red fibers require oxygen? red
What is the muscle type for postural muscles? Slow oxidative red fibers
What is the muscle type for upper leg muscles? fast oxidative red fibers
What is the muscle type for upper arm muscles? fast glycolytic white fibers
Does mitosis create new muscle cx? NO
How does muscle cx grow? -diameter of muscle increases, sarcomeres lengthen -number of sarcomeres and mito increase
Can you grow new muscle cx? NO --> born with all of the muscle cx you will ever have
intercalated disks in cardiac muscle -separate each cardiac muscle cx -contains gap jxns which spread AP via electrical synapse
How does cardiac muscle grow? hypertrophy
Why does AP plateau after depol. in cardiac muscle? slow voltage-gated Ca channels allow more Ca to enter and lengthen time of contraction
Does smooth muscle have sarcomere? NO
Myogenic activity in smooth muscle contracts without nervous system input --> pH, O2, CO2, temp
What nervous system does skeletal muscle belong to? somatic nervous system
What nervous system does smooth and cardiac belong to? autonomic nervous system
How does the body store energy in relation to creatine phosphate and ATP? transfers phosphate from ATP to creatine to make Creatine-P
Why is creatine phosphate useful? immediate creation of ATP without glycolysis or TCA cycle
What does creatine-P do? transfers P to ADP
Muscles can only exert a pushing / pulling force? pulling
How are relaxation and elongation different? -all muscles can relax once myosin heads are unbound -not all muscles can elongate
What are flexors? biceps and hamstrings
What are extensors? triceps and quadriceps
What do flexors do? decrease angle of joint btwn 2 bones
What do extensors do? increase angle of joint btwn 2 bones
Contraction causes ____ out of 2 bones to move one
What is the muscle called that is attached to stationary bone during mvmt? origin
What is the muscle called that is attached to bone that moves? insertion
Abductor / adductor? -abductor = moves body away from body's midlline -adductor - moves part of body towards body's midline
What are some examples of connective tissue? cartilage, bone, ligaments, tendons, fat, blood
What is characteristic of white muscle? fast but tires easily
What is characteristic of red muscle? high endurance but slow
Mito: white muscle vs. red muscle white muscle has few mito while red muscle has a lot of mito
Myosin power stroke causes actin to move towards ____ line. M line
How to detach myosin head from actin? 1. ATP binding detaches myosin head 2. ATP hydrolysis is needed for de-powerstroke to unbend myosin head
____ binds to troponin and troponin moves ______. calcium and tropomyosin
terminal cisternae enlarged areas of the SR surrounding the t-tubules that store calcium
Muscle contraction steps nerve stimulates muscle, AP goes into muscle through t-tubules, stimulate SR to release calcium, actin-myosin action
squamous flat
What are simple epithelium cx good for? absorption, secretion, filtration, diffusion
What are stratified epithelium good for? protection against abrasion
What are endothelial cells? lines inside of organs and blood vessels --> aka simple squamous epithelium
What is connective tissue? cx + extracx matrix
What is extracx matrix? fibers (collagen) and glue to hold everything together
What do fibroblasts do? make connective tissue (i.e. fats, tendons, ligaments)
What do chondroblasts make? cartilage
What do hematopoietic stem cx make? blood
"-blast" stem cx actively producing matrix
"-cyte" mature cx doing housekeeping
What is most common extracx fiber type? collagen
What are the fiber types for connective tissue and what is each known for? collagen (strong) elastic fibers (stretch) reticular fibers (branch and form nets)
What is loose connective tissue? loose fibers with lots of fluff (fat)
What is dense connective tissue? dense fibers with little fluff (tendon, ligament)
What is cartilage? connective tissue made of chondrocytes + matrix --> no blood vessels
macrophages phagocytize pathogen and then present antigen on cx
neutrophils phagocytize pathogen and destroy it
mast cx release histamine during allergy to bring inflammation
natural killer cx kill infected / abnormal cx (esp. cancer cx)
dendritic cx present antigen to T-cx during cell-mediated immunity
Where are all lymphocytes formed? bone marrow
Where do T-cx mature? thymus
Cytotoxic T-cx recognize antigen on infected cx and signal for apoptosis
Helpter T-cx recognize antigen and signal for activation of macrophages, T, and B-cx
B-cx form _____ and ______ when exposed to antigen. plasma cx and memory cx
Plasma cx role in immune response. secrete free antibody that can either act on its own or binds with mast cx and antigen
Memory cx role in immune response stick around in case same antigen attacks in future
Where do b-cx differentiate? bone marrow
ALL blood cx and immune cx arise from ? bone marrow stem cx
What is role of spleen for WBC and RBC? -site for WBC to reside and proliferate -removes old RBC and platelets -filters blood and removes foreign antigens
Interferons in immune response? interfere with virus replication
Complement px in immune response? punch holes in pathogen mem.
Why are WBCs recruited faster during a fever / inflammation? WBC are more active at higher temperature
Immunity neutralization pathogen can't adhere to host cx
Immunity opsonization easier for phagocytosis
Complement activation kills infected cx by punching holes in cx mem
What does the antibody consist of? 2 light chains and 2 heavy chains linked by disulfide bonds
Hypervariable regions of antibody tips of Y in antibody that are unique
Which T-cx are activated with an extracx pathogen? helper T-cx --> activate macrophages and B-cx
Which T-cx are activated with an intracx pathogen? cytotoxic T-cx
What creates inflammation? histamine, prostaglandins, lymphokines
How do cx stop bacteria? inflammation --> high temp stops bacteria growth
How do cx stop virus? viral infected cx produce interferon to prevent viral replication
How do macrophages destroy cx material? lysozymes
What do vaccinatins create? development of lasting memory cells
Where do B-cx mature? spleen and lymph nodes
How to antibodies fight infection? -bind to foreign antigens and allow other immune cx to phagocytize -cause agglutination
What are plasma cx? specialized B-cx that produce and secrete antibodies
Basic outline of humoral immunity extracx microbe, B-cx secrete antibody, phagocytize
Antigen-binding region specific polypeptide sequence that will bind ONE antigen
constant region recruitment and binding of other immune modulators (i.e. macrophages) --> doesn't bind antigen
How long is primary immune response vs. secondary? 20 vs. 5
Humoral vs. cx-mediated immunity -Humoral = extracx pathogen --> phagocytize -cx-mediated = pathogen that has invaded cx --> perforin
What type of cx does HIV affect? helper T-Cx
What does helper T-cx secrete to coordinate immune response interleukins aka lymphokines
What does helper T-cx recruit? B-cx, killer T-cx, suppressor T-cx
How does killer T-cx kill viral-infected cx? release perforin
Why are killer T-cx so effective? release perforin so can attack many cx since don't phatocytize
Why is use of immunosuppressants necessary during cancer or after organ transplant? killer T-cx will try to destroy implanted organ
epitope specific part of antigen that is recognized by immune system aka antigenic determinant
Why do B-cx have more rough ER? rough ER is responsible for production of secretory px
MHC Class I px on every cx that presents to killer T-cx
MHC Class II px on immune cx (macrophages) that present to helper T-cx
MHC Class I vs. MHC Class II in terms if type of response MHC I - cx response MHC II - humoral response
What are antigens made of? px and carbs on cx
What if immunity can't differentiate between self and non-self? autoimmunity
What type of rxn are allergies? hypersensitivity
Antigens stimulate B-cx to ______ while T-cx to _______. -produce antibodies -kill directly
Type of pathogen: Cx-mediated vs. humoral Cx-mediated = viral and fungal Humoral = bacterial
Type of passive immunization. antibody transfer across placenta and breastmilk
Are antibodies used in cx-mediated response? NO
Shape of skeletal, cardiac, and smooth muscle? skeletal - non branched cardiac - branched smooth - tapered
What gives striated appearance? presence of sarcomeres
A bands are (dark /light) and I bands are (dark / light) -dark -light
Which types of muscles have sarcomeres? skeletal and cardiac
What gives nonstriated appearance? no sarcomeres
What do all muscles use in common? myosin, actin, and sliding filament model
What do somatic motor nx control? skeletal muscles
What do autonomic motor nx control? involuntary muscles (smooth and cardiac)
Neuromuscular junction nerve (axon terminal) meets muscle (motor end plate)
Motor end plate sarcolemma that synapses with motor nx
Ultimately, what causes a muscle to contract? AP
Both sympathetic and parasympathetic are motor nx that innervate ______ muscles involuntary
During sympathetic response, pupils _____; parasympathetic, pupils _____. dilate / constrict
What are main fxns of skeletal system? -structure -calcium storage -physical protection
What are long bones and example? shaped like a rod (i.e. arm, leg, finger)
What are short bones and example? shaped like a cube (i.e. wrist, ankle)
What are flat bones and examples? flat bones (i.e. sternum, shoulder, ribs, skull)
What are irregular bones and examples? Weird shapes (vertebrae and hip)
What is a joint? bone meets bone --> can be mobile or non-mobile
Mobile joints vs. non-mobile joints -have synovial fluid cavity to lubrication -connect bone to bone with cartilage or fibers
Ball and socket joint example shoulder or hip
Hinge joint elbow
Gliding joint wrist
Immobile joint skull and rib to sternum
Where is cartilage found? ear, nose, epiglottis, ends of bones in joints, knee, btwn vertebrae
What are bone cells? osteocytes
What is the extracx matrix of bone made of? calcium-px matrix --> calcium, collagen, glue
What is membrane outside of bone called? periosteum
Growth in length: osteoblasts vs. osteoclasts osteoblasts lengthen and osteoclasts shape
Growth in diameter: osteoblasts vs. osteoclasts osteoblasts widen and osteoclasts remove bone tissue from inside to keep bones light
Osteoblasts vs. osteocytes -osteoblasts = stem cx that give rise to osteocytes -osteocytes = mature bone cx that build bone
What does bone marrow store? blood stem cx and adipocytes
perichondrium connective tissue that surrounds cartilage of developing bone
What is synovial fluid? lubrication and has phagocytes
axial vs. appendicular axial (spine) vs. appendicular (arms)
Endochondral ossification cartilage template replaced by bone
Diaphyses cylindrical shafts with marrow
Epiphyses dilated ends made of spongy bone and compact bone
epiphyseal plate site of longitudinal bone growth
Bone is storage site for ____ and_____ to maintain mineral homeostasis. calcium and phosphate
hydroxyapatite crystals calcium, phosphate, and hydroxide ions --> strength and mineral storage
How are osteocytes formed? osteoblasts trapped btwn lamellae
osteon cylinders in bone with blood vessel and nerve --> includes lamellae and haversian canal
What kind of marrow does spongy bone have? Compact bone? -spongy bone = red and yellow marrow -compact bone = yellow marrow
What is main fxn of osteocytes? exchange nutrients and waste with blood --> can also build bone
What materials are necessary to build bone? collagen and inorganic ions
What must be released to move any voluntary muscle? AcH
What is the pH of skin? 5.6
What allows macrophage to engulf microbe? actin
During any infection, the first response is initiated from? innate immunity
How does macrophage destroy contents? Creates a phagosome and fuses with a lysosome to form a phagolysosome
What is the first line of immune defense? skin, mucous, etc.
What is the second line of immune defense for innate immunity? macrophages
What do helper T-cx release to active B-cx or T-cx? interleukins
Do antibodies destroy foreign antigens? NO --> recognize and identify them
Why does immune system normally avoid attacking it's own cells? suppresses cells specific to body's own antigen s
Where are antigens carried? on cx surface --> NOT on DNA, RNA, chromo
How do antibiotics work (2)? -kill bacteria -stop bacteria from multipling
Where do leukocytes gravitate to? inflammation
What are the causes of cancer? -DNA damage -uncontrolled cx division
Relate striated muscle, KE, and PE. striated muscle turns PE stored in glucose to KE of muscle contraction
Do antibiotics cause mutations? NO
What do lymphocytes differentiate into? T-cells and B-cells
Osteoblasts are eventually converted into/ osteocytes
What do osteocytes do? maintain healthy bone tissue during times of non-synthesis
Do osteoblasts divide? NO
How do osteoclasts cause bone resorption? use carbonic anhydrase to release HCl
Cardiac and smooth muscles depend on what type of junction? gap junction --> skeletal can contract independently and do NOT rely on gap junctions
What are cardiac muscle cell gap junctions known as? intercalated disks
How do smooth muscles differ from skeletal muscles? no T-tutubles, no striations, no troponin, no tropomyosin --> myosin and actin filaments are present
What are the 2 locations for amylase? mouth and s. intestine
Does Vitamin D increase / decrease blood calcium? increases
What is the largest solid organ in the body? liver
What are mature osteoblasts called? osteocytes
What is the ntm used by parasympathetic to decrease heart rate? Increase heart rate? acetylcholine / norepinehrine
Where does calcium for muscle contraction come from? extracx environment and sarcoplasmic reticulum
lamellar bone vs. woven bone -woven bone = immature -lamellar bone = strong and mature
What are types of lamellar bone? spongy and compact
All muscle stimulating neurons produce what ntm? acetylcholine
In a muscle contraction, which bands become smaller? H and I
Where does Krebs occur? mito
Red vs. white fibers -red = slow contraction, full of mito -white = fast contraction, no mito (glycolysis)
What are myoblasts? precursors to muscle skeletal cells
Marcrophages are part of what immunity? innate, nonspecific immunity
What cx type gives rise to macrophages? monocytes
How are plasma cells formed? B-cx formed by bone marrow are converted into plasma cx during active infection
What do antibodies do? bind invading bacteria to make them easier to be ingested by phagocytes
Does cx-mediated response involve antibodies? NO
What are the body's 2 methods for regulating homeostasis? endocrine and nervous system
Innate vs. humoral immune response -innate = macrophages, neutrophils, natural killer cx -humoral immunity - B-cx
Why are helper T-cx so important? control immune response to every antigen -without T-cx --> no immune response -macrophages and other nonspecific immune cx find foreign antigens and show them to helper T-cx (decide whether or not to mount response)
T/F: An antigen is digested by the lysosome before being presented to T-lymphocyte TRUE
What is inflammation? white blood cell (leukocyte) response to a bacterial infection --> increased vascular permeability
leukocyte vs. lymphocyte -leukocyte = white blood cx -lymphoctye = special type of white blood cx -T and B-cx
What are the 2 subdivisions of acquired immunity? cell-mediated and humoral immunity
Does parasympathetic / sympathetic innervation determine cardiac baseline? parasympathetic
What is the pH of skin? 5.6
What is the first line of defense and second line of defense in innate immunity? -skin, mucus, cilia -macrophages
basophils inflammatory reactions esp. those involved with asthma and allergies
What is cell-mediated immunity most effective against? virus-infected cells, microbes that survive phagocytosis, microbes that infect non-phagocytic cell
Cytokines cell-signaling communication molecules used during immune response
T-cx mark invaders for destruction by? macrophages
Is gray matter / white matter myelinated? -gray matter - unmyelinated -white matter -myelinated
What type of cell myelinates central nervous system? oligodendrocytes
What type of cell myelinates peripheral nervous system Schwann cells
muscarinic rx are found in? nicotinic are found in? CNS / NS
What type of channels are found at axon terminal? calcium
Where is the greatest conc. of sodium channels found? nodes of Ranvier
Created by: 507935299