Bolded Exam #1 Flashcards
functional contracting unit of the muscle fiber
sarcomere
thick filament on muscle filament
myosin
thin filament on muscle filament
actin, tropomyosin, troponin
filamentous protein that runs along the groove of each twisted actin filament - function is to block the myosin-binding sites on actin
tropomyosin - must be moved out of the way during contraction so that myosin can bind to actin
A complex of 3 globular proteins located at regular intervals along the tropomyosin filaments
troponin - T, I, C
attaches the troponin to tropomyosin
troponin T
along with tropomyosin inhibits the interaction of actin and myosin by covering myosin-binding site of actin
troponin I
is a Ca2+ binding protein that plays central role in the initiation of contraction
troponin C - binds to troponin C and then alters shape to remove tropomyosin from the myosin binding sites
As long as intracellular Ca2+ is _______ cross-bridge cycling cannot occur and the muscle relaxes
LOW
What is it called when intracellular Ca2+ concentration never returns to the low levels that exist during relaxation? Results in continued binding of Ca2+ to troponin C
Tetanus - occurs when muscle is continually stimulated and there is insufficient time for the SR to re-accumulate Ca2+
ICF calcium remains high
hypertrophy causes what in the muscle? what causes it?
increase in actin and myosin
caused by near maximal force development (weight lifting)
myofibrils split
formation of new muscle fibers is called what? what causes it?
hyperplasia
-caused by endurance training, but this is rare occurrence otherwise?
lengthening of the muscle is normal and causes what?
increased shortening capacity, and increased contraction velocity
- this occurs with normal growth
- no change in force development?
smooth muscle contains both ______ and _____ filaments, but does not have ______
how does smooth muscle contraction happen and what is it called?
myosin and actin
- does NOT have troponin
- contractile process activated by Ca2+ ions and ATP that is broken down to ADP
pull in opposite directions of actin filaments - this allows smooth muscle to contract about 80% of its length vs 30% in skeletal muscle
-this is called side polar cross-bridge
The 2 major neurotransmitters of smooth muscle?
norepinephrine and ACh
- both excitatory and inhibitory
- when ACh excites a muscle fiber, norepinephrine ordinarily inhibits it;
conversely when norepi excite ACh normally inhibits
*really it’s the type of receptor that these bind to as to whether it’s an excitatory or inhibitory signal
Since there is no troponin in smooth muscle, how does myosin interact with actin?
The interaction of myosin and actin is controlled by binding of Ca2+ to a protein called calmodulin
negative feedback is what and promotes what?
- negative feedback returns body to normal/homeostasis
- cancels out the original response
- ex. when blood sugar spikes and insulin restores normal blood sugar levels
- negative feedback promotes STABILITY
positive feedback is what and promotes what?
- exaggeration or more of the original response
- may be unstable or normal
- promotes instability/disease BUT can be normal
- normal ex: oxytocin release during childbirth stimulates labor contractions; platelets and clotting cascade
proteins in the cell membrane provide _____
selectivity with integral (throughout membrane) and peripheral (on one side) - can act as enzymes, receptors, channels
*provide SELECTIVITY to a membrane
cholesterol in the plasma membrane generally decreases _____ and _____ but increases membrane ____ and ______
Decreases fluidity and permeability, but increases membrane flexibility and stability
ATP is converted to ____ to produce energy. What bonds are broken to produce this energy?
adenosine triphosphate - chemical bonds b/w the 2nd and 3rd phosphate groups contain abundant energy and the rupture of the terminal phosphate bond produces energy
Simple/passive diffusion
Why does this movement occur?
Remember that diffusion will not occur if?
ion moves from higher concentration to lower concentration down concentration gradient
- the movement is to equalize the charge across the membrane
- diffusion will not occur if the membrane is non-permeable to the molecule
3 factors that influence diffusion?
concentration difference, electrical potential (EMF), and pressure difference
osmosis
passive transport of fluid across a membrane from an area of lower solute concentration to an area of higher solute concentration
Primary active transport
uses energy to move ions across the membrane - ex Na/K/ATPase pump (carrier protein)
-uses energy b/c ions are pumped against (uphill) against concentration gradient
secondary active transport
transport driven by the energy stored in the concentration gradient of another molecule (Na+) - this is considered the driver molecule
-indirect use of energy
The Na/K/ATPase pump plays an important role in
Where are Na/K pumped and how many ions?
regulating osmotic balance by maintaining the Na/K balance so the cell does not swell and burst
- 3 Na+ pumped out, 2 K+ pumped in
- also important in establishing resting membrane potential
What is the function of Ca2+ ATPase? Where is this transport protein found?
keeps ICF calcium low (maintains a low cytosolic Ca2+ concentration)
-found in the cell membrane of the sarcoplasmic reticulum - remember the SR is considered ECF
What is the function of H+ ATPase? Where is it found?
- found in the parietal cells of gastric glands (HCl secretion) and intercalated cells of renal tubules (CONTROLS BLOOD pH)
- concentrates H+ ions up to 1 million-fold
type of tissue - a continuous cellular sheet that covers body’s surfaces, lines body cavities, forms certain glands
epithelial tissue
type of tissue - binds together and supports body structures. What does it include?
connective tissue - includes bones, cartilage, and adipose (fatty) tissue
type of tissue - has a generous blood supply, and movement and contraction is the main purpose
muscle tissue
nervous tissue - main function? properties?
main function is communication
primary properties are irritability and conductivity
decrease in cell size
atrophy
increase in cell size. examples pathological and physiological?
hypertrophy
- physiological d/t wt lifting
- pathological growth in cardiac m. size d/t HTN
increase in cell number. examples pathological and physiological?
hyperplasia -increased rate of cellular division
- physiological d/t liver regeneration, normal endometrial thickening
- pathological - acromegaly d/t pit produces too much growth factor, endometrial hyperplasia (increases r/f endometrial cancer)
replacement of one mature cell with another more immature cell. example of this from notes?
metaplasia - replacement of normal bronchial columnar ciliated epithelial cells by stratified squamous epithelial cells that don’t secrete mucous and do not have cilia
-metaplasia is considered a reprogramming of stem cells
deranged cellular growth. Refers to abnormal changes in the size, shape, and organization of mature cells
dysplasia or atypical hyperplasia
does not indicate cancer
hypertrophy caused by? trigger signals can be?
increased work demand or hormones
trigger signals can be: mechanical and trophic
Four biochemical themes to cellular injury?
- ATP depletion - loss of integrity of cell membrane
- oxygen and oxygen-derived free radicals - lack of O2 (think ATP depletion), free radicals cause destruction to cell membrane
- intracellular calcium increases - causes intracellular damage by activating enzymes. Remember intracellular calcium activates MLCK that then activates myosin
- defects in membrane permeability - found in all forms of cell injury
most common cause of cellular injury
ischemia vs anoxia
hypoxic injury
ischemia - arteriosclerosis and thrombosis common causes (myocardial adaptation here)
anoxia - total lack of oxygen, sudden obstruction (eg. embolus) - complete anoxia = myocardial infarction
what is the cellular response to hypoxic injury?
decreases in ATP (only 2 ATP created d/t anaerobic metabolism) cause failure of the Na/K/ATPase pump which causes Na+ to not be released from the cell and it then swells
- this is the first change from hypoxia and is reversible when the cause is eliminated
- first manifestation of injury to cells
when additional injury occurs when oxygen is restored? what causes this?
reperfusion injury - influx of O2 that is metabolized and leads to production of free radicals like superoxide and hydrogen peroxide. Free radicals damage cell membranes –> Ca2+ overload
physical injuries that cause cellular injury are both ______ and _____
unintentional and intentional (remember poisonings can be unintentional)
- medications are leading cause of child poisoning
- medication errors in healthcare
hypothermic cellular injury - what does it cause, and what does it produce?
- slows cellular metabolic processes
- produces reactive oxygen species
hyperthermic injury - examples?
heat cramps, heat exhaustion, heat stroke, malignant hyperthermia, neuroleptic malignant syndrome, drug-induced hyperthermia, burns, overheating - SIDS?
ionizing radiation horizontal transmission
cells not in the directly radiated field are affected by the radiation (bystander effects)
ionizing radiation vertical transmission
genomic instability: generations of cells derived from an irradiated progenitor cell appear normal, but over time lethal (irreversible) and nonlethal mutations appear
cellular swelling is also called what? caused by? associated with?
oncosis!
- most common degenerative change
- caused by shift of extracellular water into the cells
- increase in ICF Na+ which draws in water
- Reversible
- sublethal
- early manifestation of almost all cell injury
- associated with hypokalemia, high fever, certain infections
necrosis - what happens to the cell membrane? includes what?
- necrosis includes inflammatory changes
- cell membrane swells and forms membrane blebs - at this point the cell could recover, but if the injury progresses then…
- breakdown of plasma membrane, organelles, and nucleus = leakage of contents
- once broken down ingested by immune cells
apoptosis - doesn’t include what? what does it involve? what are fragments considered? remember that it can occur ______ or _______
- doesn’t include inflammatory changes
- also forms membrane blebs + causes condensation of chromatin
- breaks into fragments, but cell membrane remains intact
- fragments are considered apoptotic bodies - and these are “dropped off”
- is programmed cell death
- can occur normally or pathologically
- dysregulated apoptosis is excessive or not enough - can lead to cancer, autoimmune disorders, neurodegenerative diseases, and ischemic injury
frailty - causes problems with?
wasting syndrome of aging
-mobility, balance, muscle strength, motor activity, cognition, nutrition, endurance, falls, fractures, and bone density
DNA replication - role of DNA polymerase…REMEMBER DNA vs RNA polymerase. What are the complementary base pairs in DNA?
Purines vs Pyrimidine
DNA polymerase pairs the complementary bases - adenine-thymine; cytosine-guanine
DNA polymerase adds new nucleotides and “proofs” the new protein; if not correct, the incorrect nucleotide is excised and replaced
pyrimidines - cytosine and thymine
in RNA the pyrimidine are cytosine and uracil
describe transcription and translation and check this with notes
…
polyploid cells - what are they, and examples of this? What happens if this occurs?
a euploid cell (multiple of the normal number of chromosomes) that has more than the diploid number.
Triploidy (3x23): a zygote that has three copies or each chromosome
tetraploid (4x23): 4 copies
*TRIPLOID AND TETRAPLOID fetuses DO NOT SURVIVE or are stillborn or spontaneously aborted
- sometimes this can occur in certain tissues and is a normal process that occurs w/oxidative stress w/aging
- normal for 30% of hepatocytes
aneuploidy
somatic cell that does not contain a multiple of 23 chromosomes
Manifestations of Down Syndrome and what causes it? Increased r/f?
Trisomy 21 - aneuploidy - 3 copies of chromosome 21. Caused by nondisjunction (long suspension of egg in older women) during cell division
- occurs 1/800 live births
- manifestations = mental challenges, low nasal bridge, epicanthal folds, protruding tongue, flat/low-set ears, and poor muscle tone
- increased r/f heart disease, respiratory infections, and leukemia
sex chromosome aneuploidy more common in ______ 1/400 ____ 1/650 _____
males
one of the most common aneuploidy sex chromosome abnormalities
s/s?
what is the bolded thing that is most important to remember about this?
trisomy x - females have three X chromosomes
termed meta female
occurs in 1/1000 births
s/s include sterility, menstrual irregularity, and/or cognitive deficits
SYMPTOMS WORSEN WITH EACH ADDITIONAL X CHROMOSOME
aneuploidy of sex chromosomes usually presents less serious consequences than autosomes
…
Turner syndrome? What is it? Denoted as? Characteristics? Most important bolded detail to remember. The X chromosome is usually inherited from?
when females only have one x chromosome instead of 2 in their inherited in their sex chromosome
- denoted as 45X
- short stature, absence of ovaries (sterile) - gonadal streaks instead, webbing of neck, wide spaced nipples, coarctation of aorta, edema in feet, sparse body hair
- high number of aborted fetuses have this
- X CHROMOSOME THAT IS USUALLY INHERITED FROM THE MOTHER
Klinefelter syndrome + characteristics
sex chromosome aneuploidy (not a multiple of 23) individuals with at least XX and one Y
- male appearance, high-pitch voice, gynecomastia, small testes, sparse body hair, sometimes mental impairment, sterile
- the more X the worse the condition
Chromosomal deletions are what and what bolded genetic disorder can a deletion cause? s/s?
chromosome breakage or loss of DNA - part of the chromosome is missing
- Cri du chat syndrome “cry of the cat” d/t lack of larynx development. Also called 5p deletion!
- low birth weight, mentally challenged d/t small brain size, microcephaly, heart defects, poor muscle tone
chromosomal duplications
excess genetic material
-these conditions usually have less serious consequences
chromosomal inversion
chromosomal rearrangement in which a chromosome segment is inverted: ABCDEFG becomes ABEDCFG
-usually does not affect the individual, but does affect offspring b/c it can cause duplications or deletions
chromosomal translocation
type of translocation that is BOLDED
interchange of genetic material b/w non-homologous chromosomes
- ROBERTSONIAN: long arms of two non-homologous chromosomes fuse at the centromere, forming a single chromosome; is common in Down syndrome. Person with this is normal, but has 45 chromosomes only in each cell
- however, offspring can have serious deletions or duplications
- can cause fusion of long arms of chromosome 21 & 14
- can therefore lead to down syndrome
- trisomy 13 & 14 are not compatible with life
Pedigree chart starts with? If female called what? If male called what?
Proband - the person serving as the starting point for the genetic study of a family *usually the first person in the family diagnosed or seen in a clinic
propositus (male) or proposita (female)
A variation in a phenotype associated with a particular genotype. What can cause this? Example?
EXPRESSIVITY
- can be caused by modifier genes, environmental factors, and mutations
- EXAMPLE: von Recklinghausen disease (Type 1): autosomal dominant; mutation in normal tumor-suppressor gene, lead to tumor formation; expressivity varies from brown spots on the skin to malignant tumors, scoliosis, gliomas, neuromas, learning disabilities, HTN, seizures
males are always hemizygous for x-linked inheritance (XY)
have one x chromosome, so if inherits an X recessive gene, then he will express the disease b/c no normal allele is present to counteract the diseased allele; males are affected more often with X recessive conditions
-most sex-linked traits are located on X b/c Y has relatively few genes
characteristics of X-linked recessive inheritance
b/c a father can give a son only a Y chromosome, the trait is never transmitted from father to son
skips generations through female carriers
gene is passed from an affected father to all of his daughters, who, as phenotypically normal carriers, transmit it to approximately one-half of their sons who are then affected
example of an x-linked recessive inherited condition? what happens to the gene; which gene?
Duchenne muscular dystrophy - causes DELETION OF DMD gene causes dystrophin not to work properly; consequently, muscle cells do not survive
- DYSTROPHEN is not produced as usual – needed to maintain integrity of muscle cells
- death typically occurs before 20 yo
- usually can’t walk by the time they are 10-12 yo
- also affects heart and respiratory muscles
- death usually d/t respiratory or cardiac failure
Incidence rate
number of NEW cases of a disease reported during a specific period divided by the number of individuals in the population
prevalence rate
proportion of the population affected by a disease at a specific point in time
relative risk - ratio
incidence rate of a disease among individuals exposed to a risk factor divided by the incidence rate of a disease among individuals not exposed to a risk factor (RR = IR exposed/IR not exposed)
chromosome 17 often carries mutation for ______
BRCA 1
chromosome 13 often carries mutation for ______
BRCA 2
BRCA 1 & 2 mutations lifetime risk of developing BC by how much?
50-80%
Schizophrenia
severe emotional disorder characterized by delusions, hallucinations, and bizarre, withdrawn, or inappropriate behavior
-recurrence risk among the offspring of one affected parent is 10x higher than the general population
Bipolar disorder AFFECTIVE DISORDER - more environmental or genetic?
incidence in general population is 0.5%, while 5-10% among those with an affected first degree relative
minimal environmental influence - more genetic
patients with bipolar disorder can have psychotic symptoms (psychosis) and hallucinations
genetic predisposition can be altered by?
environmental choices - lifestyle modification
benign vs malignant tumors
how do they grow? invasive? differentiated? mitotic index? spread?
benign - grow slowly, well-defined capsule, not invasive, well differentiated, low mitotic index, do not metastasize
malignant - grow rapidly, not encapsulated, invasive, poorly differentiated, high mitotic index, can spread distantly (metastasis)
remember that benign tumors can be lethal
…
benign and malignant tumors are named according to…
the tissues from which they arise and include the suffix -oma
malignant epithelial tumors are referred to as…
carcinomas
malignant tumors that arise from or form ductal or glandular structures
adenocarcinomas
malignant connective tissue tumors are referred to as
sarcomas
cancer - arise from lymphatic tissue
lymphomas
cancer - from blood forming cells
leukemia - think leukocytes
