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breakdown of very long chain fatty acids via beta oxidation
In most organs, what do epithelial cels constitute?
parenchyma; or the functional parts of the organ
Connective tissues are the main contributors to the _.
stroma or support structure
single celled organisms that are similar to bacteria but have genes and metabolic pathways more similar to euk
Explain the two cell wall types in bacteria.
gram positive: have peptidoglycan; provides protection from host's immune system; lipoteichoic acid
gram negative: very thin; contain peptidoglycan in smaller amounts; have outer membranes with phospholipids and lipopolysaccharides, which trigger larger response in humans than lipoteichoic acid
traits that increase how pathogenic a bacterium is
integration of foreign genetic material into the host genome
bacterial form of mating; involves conjugation bridge; donor male and recipient female; sex pili
requires a vector to carry genetic material from one bacterium to another
What surrounds a virus?
- a capsid, whcih is a protein coat
- an envelope which surrounds the capsid
positive sense viruses
genome directly translated to functional proteins
negative sense virus
require synthesis of RNA complementary to negative sennse then protein synthesis
must go to the nucleus in order to be transcribed to mRNA, which tehn goes to the cytoplasm, where it is translated to protiens
small plant pathogens consisting of a very short circular single stranded RNA
the cell determines if the DNA is in good enough condition for synthesis; restriction point
require the presence of the right cyclins, which increase and decrease during specific stages; they bind to CDKs, creating complexes that can phosphorylate transcription factors
homologous chromosomes are separated; reductional division
separation of sister chromatids; equational division
WHat does a cell in meiosis I look like?
96 sister chromatids and 46 chromosomes, which are organized into homologous pairs
What does a cell in meiosis II look like?
46 chromatids in 23 chromosomes
refers to the tendency for genes to be inherited together; genes that are located further from each other are less likely to be inherited together and more likely to undergo crossing over relative to each other
each chromosome of paternal origin separates from its homologue of maternal origin and either chromosome can end up in either daughter cell
short rest period during which chromosomes partially recoil between meiosis I and II
What are the two functional components of the testes?
seminiferous tubules: produces sperm (sertoli cells nourish them)
interstitial cells of Leydig: secrete testosterone nad otehr male sex hormones
flagella gain motility
Explain passage of sperm.
vas deferens-> ejaculatory duct--> urethra
contribute fructrose to nourish sperm
along with seminal vesicles, they give fluid alkalinity to allow it to survive int he acidic female tract
produce clear viscous fluid that cleans any remnants of urine and lubricates urethra during arousal
diploid stem cells (spermatogonia)--> primary spermatocytes--> secondary spermatogcytes--> spermatids--(maturation)--> spermatozoa
each sperm head is coverted by an acrosome derived from the Golgi and necessary to penetrate the ovum
multilayered sacs taht contain, nourish, and protect immature ova (eggs)
Explain egg migration.
ovulated through peritoneal sac
drawn into fallopian tube
if fertilized, the fetus is developed in the uterus
oogenesis differs from spermatogenesis how?
1) no undending supply of stem cells; all are formed during fetal development
all oogonia exist as primary oocytes by irth; after mearching menarche, one will complete meiosis I, producing a secondary oocyte and a polar body; the secondary oocyte is arrested in metaphase II and will not move forward unless fertilziation occurs
oocytes are surrounded by two layers:
zona pellucida: surrounds oocyte and is acellular mix of glycoproteins that proteect oocyte and contain things for sperm to bind
corona radiata: lies outside and adhered to oocyte during ovulation
When does meiosis II occur in an oocyte?
when sperm penetrate the laers
gonadotropin-releasing hormone: triggers anterior pituitary to release FSH and LH
FSH does what in males?
stimulates SErtoli cells and triggers sperm maturation
LH does what in males?
causes interstitial cells to produce testosterone
FSH does what in fems?
estrogen is secreted in response to it
estrogen does what
aside from developing female reproductive sysem adn sexual characteristics, it thickens lining of uterus
Proggesterone does what?
secreted by corpus luteum in response to LH; maintains the endometrial lining
Follicular phase of the menstrual cycle.
sheding of uterine lining
GnRH increases--> FSH and LH secretion
follicles are developing, secreting estrogen, which turns off GnRH and, as a result, LH and FSH
when estrogen cycles reach threeshold; it results in positive feedback and FnRH, FSH, and LH levels spike
LH causes formation of corpus luteum from ruptured follicle, which secretes progesterone; estrogen levels still high
implantation doesn't occur; corpus luteum loses stimulation
zygote develops into bastocyyst that implants in uterine lining and secretes human chorionic gonadotropin; critical during first trimester
What happens when the sperm comes into contact with the secondary oocyte's cell membrane?
it forms a tubelike structure called the acrosomal apparatus, which extends to and penetrates the cell membrane
After penetration of the sperm, what happens?
the cortical reaction, a release of calcium ions to depolarize the membrane of the ovum to prenet fertilization by multiple sperm and to increase the metabolic rate of the newly formed diploid zygote
What are the steps after zygote?
cleavage: zygote undergoes rapid mitotic cell divisions, forming a morula
blastulation: formation of blastula (hollow ball of cells with luid filled inner cavity called the blastocoel), also known as blastocyst, which has a trophoblast adn an inner cell mass
burrows into endometrium
gastrulation: generation off the three distinct layers
cells that can still develop into complete organisms
cells with fates that are already determined
surround blastocoel and give rise to chorion and later placenta
inner cell mass
protrudes into blastocoel and gives rise to organism itself
extraembryonic membrane that develops into the placenta
begins with small invagination in blastula (archenteron); cells move towrad invagination, eliminating blastocoel
this forms the gastrula
opening of archenteron is blastopore
give rise to integumentm; lens of the eye; nervous system, ear
musculoskeletal, circulatory, excretory, and sex organs, as well as conective tissue layers of digestinve, respiratory systems and adrenal cortex
epithelial lining of digestive adn respiratory tracts, pancreas, thyroid, bladder and distal urinary tracts
ability of one group of cells to influence the fate of other nearby cells
development of nervous system:
1) rod of mesodermal cels called notochord form axis, influencing cells to form neural folds, which surroudn a neural groove
the neural folds fuse into neural tube, with neural crest cells at tip
may cause nearby cells to follow a particular developmental pathway
When do totipotent cells lose their ability to differentiate into anything?
after the sixteen cell stage and after a few more cycles of cell division when they differentiate into three gern cell layers
signals that act on teh same cell that secreted the signal in teh first cell
signals act on cells in the local area
cell stimulates receptors of adjacent cell
invovle secrted hormones that travel through the bloodstream
Umbilical arteries carry __ and umbilical veins carry __
blood away from the heart (deoxygenated)
blood toward the heart (oxygenated)
What are the three shunts a fetus goes through to direct blood away from the lungs and liver?
1) foramen ovale: one-way valve that connects the right atrium to teh left atrium, allwoing blood entering the right atrium to flow into the left atrium instead of the right ventricle so as to carry out systemic circulation
2) ductus arteriosus: shunts leftover blood from teh pulmonary artery to teh aorta
3) ductus venosus: shunts blood returning from placenta via the umbilical vein directly to the inferior vena cava to bypass the liver
What happens in the first trimester?
major organs begin to develop; endochondral formation
embryo becomes known as fetus
What happens in the second trimester?
fetus undergoes trememdous growth; takes on human appearance
What happens in the third trimester?
rapid growth and further brain development; antibodies transported by active transport from mom to fetus
accomplished by utermine smoth muscle, coordinated by prostaglandins and peptide hormone oxytocin
1) cevix thins out and sac ruptures
2) strong uterine contractions
3) placenta and umbilical cord expelled (afterbirth)
axons bundled together that carry only one type of info
nourish neurons and form the blood brain barrier
line ventricles of brain and produce CSF
phagocytic cells that ingest and break down wast and pathogens in the CNS
Concentration of Na and K inside and outside neuron
Na is higher outside; K is low outside
caused by inhibitory input; it is lowering the membrane potential from its resting potential; makes neuron less likely to fire
additive effects of multiple signals
multiple signals are integrated during a relatively short period of time
the additive effects are based on the number and location of the incoming signals
what are the two types of refractory periods?
absolute refractory period: no amount of stimulation can cause another action potential to occur
relative refractory period: there must be greater than normal stimulation to cause an action potential because the membrane is starting from a potential that is more negative than its resting value
Greater cross sectional areas allow for what?
faster propagation due to decreased resistence
How is neurotransmitter removed from the cleft?
1) breakdown of NT; ex: acetylcholinesterase breaks down acetylcholine
3) simple diffusion
cell bodies of sensory neurons are __.
dorsal root ganglia
difference between somatic and autonomic nervous system
Somatic goes directly from spinal cord to muscle
autonomic requires two neurons, the preganglionic and the postganglionic neuron
Epinephrine causes what for blood vessels.
constriction of blood vessels in all but active muscle
bind to extracellular receptors
response is rapid but short lived
travel in bloodstream; don't need carriers
produced primarily by gonads and adrenal cortex
easily cross cell membrane and bind to recepotors intracellularly or intranuclearly
receptors then bind to DNA
not water soluble and must be carried to travel
amino-acid derivative hormones
less common but include epinephrine, norepinephrine, etc
catecholamines bind to G protien-coupled receptors, while thyroid hormones bind intracellularly
part of the hypothalamus that receives some of the light input from retinas and helps to control sleep-wake cycles
The hypothalamus secretes compounds into the __, which is a blood vessel system that directly connects the hypothalamus with the anterior pituitary
hypophyseal portal system
What are the tropic hormones released by the hypothalamus?
GnRH--> causes release of FSH and LH released from anterior pituitary
GHRH (Growth hormone-releasing Hormone)--> Growth Hormone (from ant. pit.)
Thyroid-releasing hormone (TRH)--> TSH (ant. pit., which acts on thyroid to release T3 and T4)
Corticotropin-releasing factor (CRF)--> adrenocorticotropic hormone (ACTH) (which causes cortisol to be released from adrenal cortex)
Prolactin-inhibiting factor: causes decrease in prolactin secretion
Relationship between posterior pituitary and hypothalamus
hypothalamus directly sends signals to release oytocin and antidiuretic hormone
- involved in bonding behavior
- uterine contraction
- milk letdown during lactation
Antidiuretic hormone (ADH)
increases reabsorption of water in the collecting ducts of the kidneys secreted in response to increased plasma osmolarity (increased concentration of solutes)
increases permeability of the duct to water
What are the products of the anterior pituitary?
- Prolactin: stimulates milk production (dopamine secretion decreases it)
- Growth hormone
- capable of resetting the basal metabolic rate of the body by making energy production more or less efficient, as well as altering the utilization of glucose and fatty acids
- lead to increased cellular respiration
produced by C-cells of the thyroid tissue;
acts to decrease plasma calcium levels in three ways:
- 1) increase calcium excretion from the kidneys
- 2) decreased calcium absorption from the gut
- 3) increased storage of calcium in the bone
- decreases excretion of calcium by kidneys
- increases absorption of calcium in the gut
- increases bone resorption, thereby freeing up calcium
antagonistic hormone to calcitonin
activates vitamin D
Adrenal glands contain what?
cortex and medulla
cortex releases corticosteroids--glucocorticoids, mineralocorticoids, and cortical sex hormones
steroid hormones that regulate glucose levels; affect protein metabolism
cortisol and cortisone: both raise blood glucose by increasing gluconeogenesis and decreasing protien synthesis; decrease inflammation and immunologic responses
cortisol released in times of physical or emotional stress
aldosterone: increases sodium reabsorption int he distal convoluted tubule and collecting duct of the nephron; water follows, increasing blood volume and pressure
plasma osmolarity does not change; maintains salt and water homeostasis
decreased blood pressure causes the juxtaglomerular cells of the kidney to secrete renin, which cleaves angiotensinogen to its active form, angiotensin I, which is converted to angiotensin II by antiotensin-convverting enzyme--> stimulates release of aldosterone
epineprhine and norepinephrine
alpha cells: glucagon
beta cells: insulin
delta cells: somatostatin: inhibits both insulin and glucagon secretion; decreases GH
The heart releases __ to help regulate salt and water balance
atrial natriuretic peptide
releases thymosin, which is important for proper T cell development and differentiation
Inhalation is __. We use our __, as well as the __ (one of the layers of muscles between the ribs) to expand the thoracic cavity.
external intercostal muscles
When we have a low pressure in the intrapleural space due to an increase in volume, what happens?
the gas pressure in the lungs is higher than the pressure in the intrapleural space, causing the lungs to expand into the intrapleural space, adn the presure in the lungs to drop;
air from the outside world will move in (negative pressure breathing)
What does the diaphragm do during inhalation?
contracts; chest wall and rib cage expand
What does the diaphragm do during exhalation?
relaxes; chest wall and rib cage contract
How can we make exhalation active?
intercostal muscles and abdominal muscles can oppose the external intercostals and pull the rib cage down
total lung capacity
max volume of air when one inhales completely
the minimum volume of air in teh lungs when one exhales completely
the difference between the min amd max volume of air in lungs (TLC-RV)
volume of air inhaled or exhaled in a normal breath
expiratory reserve volume
volume of additional air that can be forcibly exhaled
inspiratory reserve volume
volume of additional air that can be forcibly inhaled after normal inhalation
What controls ventilation?
ventilation center in the medulla oblongata
As carbon dioxide in the blood rises, what happens to the respiratory rate?
increase so more can be exhaled and levels fall
How do blood vessels regulate heat?
dilation allows large amount of thermal energy to be dissipated
contraction of capillaries conserves thermal energy
What do lungs have that help immune responses?
mast cells: have antibodies on their surfaces; when the right substance attaches, the mast cell releases inflammatory chemicals intot he surrounding area to promote an immune response
What happens when the pH of the blod is low?
signals to increase the respiratory rate are sent to the brain
Increasing hydrogen ion concentration will do what?
generate additional carbon dioxide
If the blood is too basic, what happens?
the body will slow the respiratory rate down to produce more hydrogen ions
If we want to increase or decrease the acidity of the blood, regarding the bicarbonate buffer, what do we look at?
H+ because H+ is a stronger acid than HCO3- is a base
valve between right atrium and right ventricle
tricuspid (three leaflets)
valve between left atrium and left ventrical
mitral; bicuspid valve (two leaflets)
electric conduction of the heart
- Impulse initiation occurs at the SA node-->
- signal reaches AV node, which sits at junction of atria and ventricle.
Signal delayed there untle ventricles fill completely
signal travels to bundle of His, embeldded int he interventricular septum, adn to Purkinje fibers, which distribte the electrical signal through the ventricular muscle
results in increase of atrial pressure that forces blood into the ventricles; extra volume of blood is called the atrial kick
Parasympathetic signals for the heart are provided by _
the vagus nerve
ventricular contraction and closure of the AV valves; blood pmped out of ventricles
heart is relaxed, semilunar valves close, and blood from atria fill the ventricles
total blood vollume pumped by a ventricle in a minute
CO= HR X SV, where HR is the heart rate in beats per minute and the SV is the stroke volume (volume of blood pumped per beat)
Characteristics of arteries
highly muscular and elastic--> resistance
left heart must generate much higher pressure to overcome resistance caused by systemic arteries
Characteristics of veins
thin walled and inelastic
carry blood against gravity and so require skeletal muscle to help move blood
blood passes through two capillary beds in series before returning to heart
hepatic portal system
blood leaving the capillary beds int eh walls of the gut pass through the hepatic portal vein before recching the capillary beds in the liver
hypophyseal portal system
blood leaving capillary beds in hypothalamus pass through capillary be in anterior pituitary to allow paracrine secretion
renal portal system
blood leaving glomerulus travels through efferent arteriole before surrounding nephron in a capillary network called the vasa recta
measuremet of how much of the blood sample consists of RBCs
granulocytes v. agranulocytes
g: neutro, eosino, basophils; granules are visible
a: lympho; mono
Lymphocyte maturation may take place in one of three locations
- mature in spleen or lymph nodes: called B cells
thymus: T cells
responsible for antibody generation
kill virally infected cells and activate other immune cells
Blood Type A produces __ antigens and __ antibodies.
surface protein expressed on RBCs
How is BP expressed.
as a ratio of systollic and diastolic pressures
How does pressure drop in blood vessels?
pressure drops from arterial to venous circulation with the largest drop occurring across arterioles
How can Ohm's law be related to blood vessles/
V=IR can be translated to dP=CO x TPR, where dP is the pressure differential, CO is the cardiac output, and TPR is the total periopheral (vascular) resistance
Compare blood vessels to circuits.
arterioles and capillaries act like resistors in a circuit
- resistance is based on resistivity, length, and cross sectional area
- the longer a blood vessel is, the more resistance it offers
- the larger the cross sectional area, the less resistence
with the exception of the three portal systems, all systemic capillary beds are in parallel with each other. Therefore, opening capilalry beds will decrease vascular resistance and increase cardiac output
specialized neurons that detect changes in the mechanical forces on the walls of the vessel
atrial natriuretic peptide; if blood pressure is too high, it causes loss of salt
How does most CO2 exit the body?
exists in blood as bicarbonate
How does increased [H+] affect hemoglobin?
it binds, decreasing the affinity of oxygen. This is the Bohr effect; this decreased affinity allows more oxygen to be unloaded at teh tissues
What causes a higher O2 affinity of hemoglobin?
decreased permeability of Co2, decreased concentration of H+ increased pH, decreased temp, and decreased 2,3 BPG
- force per unit area that the blood exerts against the vessel walls
- generated by contraction of the heart and elasticity of the arteries
sucking pressure generated by solutes as they attempt to draw water into teh blood sttream
Explain hydrostatic and osmotic pressure as it relates to BVs.
at the arteriole end, hydrostatic pressure > oncotic pressure; net efflux of water
venule end: hydrostatic pressure < oncotic; net influx of water
The balance of hydrostatic and oncotic pressures is __.
defenses that are always active against infection; cant target specific invaders
adaptive/ specific immunity
defenses that target a specific pathogen
location of blood storage and activation of B cells, which turn into plasma cells to produce antibodies as part of adaptive immunity, more specifically humoral immubity
involved in cell-mediated immunity
proved a place for immune cells to comunicate and mount an attack; B cells can be activated here as well
first line of defense; contains ?
GI tract form of dfense
form of noncellular, nonspecific defense
classical pathway: binding of antibody to pathogen
alternative pathway: does not reqire antibodies
this system punches holes into the cell walls of bacteria
proteins that prevent viral replication and dipsersons by causing nearby cells to decrease production of both viral and cellular proteins
upregulate MHC class I and class II molecules
functions of macrophages
- presents little piences of invaders to other cells using a major histocompatibility complex
also releases cytokines, chemical substances that stimulate inflammation and recruit additional immune cells to the area
binds to pathogenic peptide and carries it to cell surface
any protein in a cell can be loaded onto this and presented, allowing montioring of helath of cells; infected cells have an unfamiliar cell
endogenous pathway: binds antigens from inside the ell
MHC class II
displayed by professional antigen-presenting cells like macrophages
these cells pick up pathogens, process them, and present them on MHC II
exogenous pathway: because antigens originated from outside
professional antigen-presenting cells include __
- dendritic cells in the skin
- some B-cells
- certain activated epithelial cells
natural killer cells
can detect downregulation of MHC and induce apoptosis in virally infected cells
phagocytic; follow bacteria by using cheotaxis and can detect bacteria after they have been opsonized
release histamine, an inflammatory mediator, allowing immune cells to move to area
release large amounts of histamine in response to allergins
What are the innate (nonspecific) cells?
- mast cell
- dendritic cells
- natural killer cells
what are the adaptive cells
- b cell: govern the humoral response
- t cell: mount the cell mediated response
production of antibodies
phenomenon in which only B or T cells that are specific to a certain pathogen are activated
B cells produce two types of daughter cells
Plasma cells: produce large amounts of antibodies
memory B cells: stay in lymph node, awaiting reexposure to same antigen
Positive v. Negative selection in terms of T cells
positive: refers to maturing only cells that can respond to presentation of antigen on MHC
negative:causing apoptosis in cells that are self reactive
Three types of T cells
helper T cells (CD4+ T cells): coordinate immune resposne by secreting chemicals called lymphokines, whcih can recruit other immune cells
cytotoxic T cells (CD8+ cells): capable of directly killing virally infected cells by injecting toxic chemicals that promote apoptosis intot eh infected cells
Suppressor (regulatory) T cells: also express CD4; help to tone down immune response once infection has been contained; turn off self-reactive lymphocytes to prevent autoimmune diseases called self-tolerance
immune system is stimulated to produce antibodies against a specific pathogen; can be natural or artificia exposure
transfer of antibodies
Functions of lymphatic systems
- 1) equalization of fluid distribution
- 2) transportation of biomolecules via lacteals (for fats)
- 3) immunity (b cells proliferate and mature in lymph nodes in collections called germinal centers
In terms of the digestive system, what do ADH and aldosterone trigger?
the sensationof thirst
In terms of the digestive system, what do glucaogon and ghrelin trigger?
feelings of hunger
In terms of the digestive system, what do leptin and CCK trigger?
feelings of satiety
What digestion first begins in the mouth?
carb and lipid digestion by salivary amylase and salivary lipase, respectively
What are the anatomical divisions of the stomach?
fundus and body, which contains gastric glands, and the antrum and pylorus, whcih contain mostly pyloric glands
What do the gastric glands respond to?
signals from teh vagus nerve
tenth cranial nerve or CN X, and interfaces with parasympathetic control of the heart and digestive tract.
What three cells do gastric glands have?
mucous cells: produce mucus to protect wall of stomach
chief cells: secrete pepsinogen
parietal cells: secretes HCl; cleaves pepsinogen to pepsin