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Biol 224 - Midterm->final
Midterm -> final (no labs)
159
Biology
Undergraduate 2
05/20/2012

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Term
What toxic byproduct is produced by the body during RNA/DNA metabolism that must be excreted?
Definition
Nitrogenous waste must be excreted
Term
Which animal group includes insects?
Definition
Arthropods
Term
According to molecular RNA and DNA sequence data, the group of animals most closely related to chordates are the __________?
Definition
echinodermata
Term
ectothermic animals allow their body temperature to increase and decrease in parallel with the temperature of the environment. Temperature regulation in ectothermic animals is an example of _________________
Definition
___ none of the above was the answer. Not a case of homeostasis.
Term
Primary brain centers for the regulation of respiration and blood pressure are located where?
Definition
in the medulla oblongata
Term
preganglionic neurons of the parasympathetic division release the neurotransmitter _______, whereas postganglionic fibers about this division release _________.
Definition
acetylcholine and acetylcholine
Term
a photon causes __________ of the cell membrane of cones and rods, inducing a signal.
Definition
a photon causes hyperpolarization of the cell membrane of rods and cones, inhibiting action potentials to create a signal.
Term
which sensory system is composed of mechanoreceptors known as hair cells?
Definition
otolith
Term
which portion of a muscle fiber does not shorten during a skeletal muscle contraction?
Definition
the A-band
Term
during the contraction of a muscle, the energy from ATP is used to ______?
Definition
to change the shape of myosin headgroup so it can bind to Actin.
Term
The acute (short term) effects of stress in humans is mediated through which neurotransmitter, long term (chronic) is mediated through which neurotransmitter?
Definition
epinephrine, cortisol.
Term
what are the plasma concentrations of sodium and potassium?
Definition
sodium: 0.30g / 100ml
potassium: 0.016g / 100ml
Term
body water and salt balance are directly influenced by what?
Definition
environmental/physiological processes.
- excretion of nitrogenous waste --> directly related to the type of environment and amount of water available in tht environment.
- respiration system --> lungs are largest surface area exposed to the environment.
- ingestion of fluid / food
- body temperature regulation (sweating) --> in mammals that produce sweat.
- cellular production of metabolic water
Term
What is metabolic water?
Definition
Water is produced as a by-product of cellular metabolism. Therefore, metabolic water is water produced through metabolic pathways.
Term
What is nitrogenous waste? why is it worrisome?
Definition
toxic by-product of protein and RNA metabolism. (predom RNA).
nitrogen is extremely reactive by itself; especially when combined with a few oxygen/hydrogen and then can interact with other molecules in the body.
Term
what does the type of nitrogenous waste depend on? describe how it would change.
Definition
The type depends on the availability of water within the environment.
1) Lots of water --> Fish dilute small amounts of ammonia or ammonium ions in a lot of water. Takes the least amount of energy.
2) terrestrial environ (mammals, most amphibians, some reptiles n terrestrial invertebrates) --> using moderate amount of energy to convert ammonia to urea, a less toxic substance. Requires moderate amount of water to diluate / excrete.
3) Birds/Insects/Most reptiles produce uric acid. In order to convert ammonia/ammonium into uric acid they use a lot of energy, but require very little while to excrete it.

**in any organism you would find all three but only one will be dominant.
Term
what is the difference between the osmoregulatory pressures in freshwater and salt water environments.
Definition
fresh water environment:
environment is hypotonic; so, water moves into the cells through osmosis. Salts move out through diffusion.

Salt Water environment:
hypertonic relative to organism.
water moves out of the body through osmosis.
salts move in by diffusion.
Term
How do marine fish deal with water and salt regulation?
Definition
Gills have specialized pumps that take sodium and chloride and pump it out, back into the water. (use ATP)
Also, have kidney that highly concentrates their urine. IE high solute, very low water content.
Term
how do fresh water fish deal with water and salt regulation?
Definition
Freshwater fish rely on osmosis to get water. However, they get too much! so, they have specialized kidneys that excrete very dilute water constantly. (however, because its all the time they lose excess salt!)
Gills have specialized pumps that pick up any salt from the environment (ATP)
Term
what is hemolymph?
Definition
blood and interstitial fluid combined in one fluid compartment
Term
what are malpighian tubules
Definition
Small tubules found in insects which extend into the body cavity where they are surrounded by lymph.
fluid moves from the tubules into the hindgut where salt/water reabsorbed.
N waste and other waste compounds are excreted together with feces through the anus.
Term
What key processes underly vertebrate kidney function?
Definition
filtration
reabsorption
secretion
Term
which gland regulates kidney function?
Definition
the adrenal gland
Term
what major pathways does urine take after the stomach?
Definition
Urine formed in each kidney collects in the renal pelvis.
From there it flows thru ureters into the urinary bladder
urine is eliminated through the urethra.
Term
What is the functional unit of the kidney? Describe its structure?
Definition
The nephron.
It a blood supply tubule.
Each nephron consists of an initial filtration component called the renal corpuscle
2) a narrow tubule (DCT, LH, ACT)extends out from the RC and empties into a collecting duct.
Term
What are (is) glomerulus?
Definition
Glomerulus are glusters of interconnected, fenestrated capillaries found in each renal corpuscle.
Fenestrated capillary = capillary with tiny holes in its walls that permid rapid flow of plasma out of the capillary
Term
How much blood flows through the kidney per minute?
Definition
about 1.2L of blood/min (there's 5L of blood in the body)
Term
What pathways does urine take through the kidney?
Definition
through the glomerulus (fenerated capillaries) into a fluid-filled space called Bowman's space, which lies within Bowman's Capsule.
Bowman's capsule drains into the proximal convoluted tubule (prox w/ respect to beginning of nephron)
then leads to the loop of Henle (hairpin like structure)
then leads to the distal convoluted tubule
the distal convoluted tubule then flows into one of the many collecting ducts in the kidney.

Summary:
Glomerulus --> Bowman's Capsule --> Proximal Convoluted Tubule --> Loops of Henley --> Distal convoluted tubule --> collecting duct
Term
Where does reabsorption of useful solutes occur? Where does reabsorption of water take place?
Definition
Reabsorption of water takes place in the descending limb (PCT) thru osmosis.
Reabsorption of solutes occurs at ascending limb (DCT) through active transport and diffusion.
Term
beginning where within the kidney system is there no longer cells or protein in the urine?
Definition
At the Bowmans Capsule, but more realistically at the descending convoluted tubule.
Term
How much blood flows through the kidney per minute and per day?
how much reabso is excreted per day
Definition
1.2 liters of blood per minute
180 liters of blood per day
there is 1-2 liters excreted per day.
Term
What role does the solute concentration gradient play in kidney function? Where is the gradient between and what is the gradient?
Definition
Movement of water by osmosis in descending limb (P.C.T) concentrates urine

Concentration gradient is different between renal cortex and renal medulla.

In the beginning, near the Bowmans Capsule, the concentration of solutes is high (70% of water / salts, 100% of amino acids / glucose).
By the Proximal convoluted tubule there is 20% of water and solutes but no amino acids or glucose.
there is only 5% of water and salts by the distal convoluted tubule.
Term
Where does reabsorption of water take place in the kidney system?
Definition
There is H2O movement in the descending limb of the renal corpuscle (IE the proximal convoluted tubule).
Term
Which hormones are associated with the kidneys and what are their functions? (mentioned ones)
Definition
Aldosterone - Increases sodium reabsorption
Antidiuretic Hormone (ADH) - increases water reabsorption by opening up more aquaporins.
Term
What are Juxtanudullary Nephrons and Cortical Nephrons with regards to kidneys?
Definition
Juxtanudullary medulla-> Type of nephron with long tubes, located nearer to the renal corpuscle and its PCT and L.H occur at a deep position. *does more work, so produces a concentrated urine.

Cortical Nephrons --> type of nephron where tubes are shorter (and so located further from the cortex). These proudce dilute urine.
Term
what inhibits ADH secretion into blood?
Definition
alcohol and caffeine.
Term
Where are true loops of Henle found?
Definition
True loops of Henle are found only in birds and mammals.
Term
How are the kidneys of desert rodents different from other rodents?
Definition
Desert rodents have very long loops of Henle, which make very concentrated urine in order to retain water.
Term
How do vampire bats deal with the excess weight/ high water concentration of blood?
Definition
When they eat, ADH is inhibited as soon as feeding begins.
ADH is the antidiuretic hormone. It increases water reabsorption. Inhibiting it will create a more dilute urine.
Term
How do fish gills increase the efficiency of oxygen exchange?
Definition
- folding of membrane increases surface area
- countercurrent exchange (IE water flowing in the opposite direction as blood flow) Ensures that concentration gradient is maintained across the capillary. (drive diffusion of O2 out of water)
Term
What is the downside to concurrent exchange?
Definition
that the blood can only ever become 50% oxygenated. Once the capillary and water have been equalibrated no diffusion of gasses will occur.
Term
what is the type of respiratory system found in insects?
Definition
the tracheal system. Air is carried directly to the tissues through small openings spread throughout the length of the insects body called spiracles.
Spiracles lead to tubes called the trachea which lead down to inside the body.
Trachea lead to smaller tubes called tracheoles which become finer and finer until they surround all major cells of the internal body.
Oxygen moves directly into cells through diffusion.
Term
What limits how big insects can become?
Definition
the size of the tracheal system. It is composed of short tubules with fairly large diameters. If they were longer, it would be harder for air to get throgh efficiently.
Term
What is the pathway, from the throat, that air takes in humans?
Definition
the throat is the pharynx.
It leads into the trachea. The beginning of the trachea is called the larynx.
The trachea splits into the Bronchus (left and right bronchus)
the bronchi, in turn, split into smaller tubes called bronchioles.
Bronchioles lead into grape-like clusters called alveoli.
Term
What type of breathing method is used by frogs and other amphibians?
Definition
Positive (force) pump is used by frogs and other amphibians.
They breathe in through their noses, then lift the floors of their mouths and close their noses to push air down into their lungs. **not very efficient
Term
What type of breathing method is used by insects, reptiles, birds and mammals?
Definition
Negative (suction) pump
interstitial muscles cause rib cage to expand. Diaphragm pushes down. Combination expands overall cavity craeting negative pressure which is relieved by a massive movement of air inwards.
**exhalation is an elastic rebound.
Term
Describe the lung structure (anatomy) of a bird. Is there a benefit to this system?
Definition
In contrast with the other major system, this lung system has added components. The anterior and posterior air sacs. Also, the parabronchi.

The benefit to this is that there is no need for residual volume. Air is unidirectional. The parabronchi increase respiratory surface due to increased contact with capillaries in a crosscurrent direction.
Term
What are respiratory pigments?
Definition
large, usually colored pigments that carry oxygen and allow animals to overcome the limited solubility of O2 in water. (proteins that carry O2)

example: hemoglobin
Composed of a protein plus a metal ion
Term
respiratory pigments are composed of what
Definition
a protein and a metal ion
Term
which metal ions are bound to respiratory pigments in diff organisms? what colors do they produce?
Definition
Iron - Red
Copper - Blue
Iron - Green
Term
where are respiratory pigments found in invertebrates and vertebrates?
Definition
In most invertebrates: dissolved in blood plasma
in most vertebrates: contained within erythrocytes (RBCs)
Term
How is blood CO2 transported?
Definition
7% of Co2 trans as gaseous CO2
23% combined with hemoglobin
70% as bicarbonate ion
Term
what is the intermediate in the pathway that converts CO2 to bicarbonate (HCO3-)
Definition
carbonic acid
Term
where is CO2 converted into bicarbonate?
Definition
Inside a RBC by an enzyme (carbonic anhydrase) that first converts it into carbonic anhydrase and then into bicarbonate.
the opposite reaction occurs in the lungs.
Term
what is the enzyme called that converted CO2 into carbonic acid?
Definition
carbonic anhydrase
Term
What are the primary ways in which the respiratory system gets modulated?
Definition
rate/depth that lungs are ventilated.
Term
In mammals, where is lung ventilation controlled from?
Definition
by the pacemaker motor neurons in the medulla oblongata.
Term
where are blood concentrations of CO2 and H detected?
Definition
by the chemoreceptors in the carotid arteries and central nervous system.
Term
what is the autonomic nervous systems role in respiration?
Definition
It controls the degree to which the smooth muscle surrounding the bronchioles is constrited.
Sympathetic nervous system is responsible for bronchial dilation.
Parasympathetic nervous system stimulates the smooth muscle and results in bronchial constriction.
Term
Yawns and sighs are controlled by what section of the brain?
Definition
the medulla oblongota
Term
What allows blood to flow through the circulatory system?
Definition
A change in pressure from one side of the tube to the other.
the heart is the pump that generates the pressure.
Term
what is a particular feature about the organisms that use diffusion for gas exchange?
Definition
They're able to be only a few cells thick.
Term
What do organisms that do not have circulator systems have instead of blood?
Definition
interstitial fluid.
Some animals circulate water in a body cavity and rely on direct diffusion with environment.
Term
Which animals groups do not have circulatory systems?
Definition
Porifera
Cnidaria
Nematoda
Echinodermata
Term
the efficiency of a circulatory system is measured by what?
Definition
measured by the quantity of substances moved through unit time is the efficiency of the system.
Term
What are the major types of circulatory system?
Definition
Open systems:
- fluid not in vessels, lack capillaries, blood bathed in cells directly.

Closed systems:
- fluid contained in vessels. Capillaries present, exchange of material across capillary wall.
Term
what is a hemocoel?
Definition
A blood filled cavity
Term
What are the consequences of a closed circulatory system?
Definition
Blood volume is smaller
Blood flow can be targeted to tissues
higher blood pressure
complexity of animal can increase
Term
what limits the complexity of the annelids?
Definition
no specialized respiratory system
heart is not well developed
Term
What are systemic capillaries?
Definition
capillaries that are not associated with the respiratory system
Term
What are respiratory capillaries?
Definition
Where gas exchange occurs with the environment, associated with the respiratory organ.
Term
What is a capillary bed?
Definition
A set of capillaries that are connected to a single arteriole and associated with specific tissues.
Term
excess fluid leakage from a capillary causes what?
Definition
edema
Term
A capillary bed is made up of what kinds of capillaries?
Definition
fenestrated capillaries
continuous capillaries
Term
What do arteries have with regards to structure that veins do not.
Definition
Arteries have a lot of smooth muscle found in the walls of arteries.
Veins have valves, arteries do not.
Term
which neurotransmitter causes vasoconstriction of the arterioles?
Definition
Epinephrine - released from adrenal gland -
Term
where does the lowest rate of blood flow occur and what does this facilitate? How does this occur?
Definition
blood flow is lowest in the capillaries.
this ensures the optimal opportunity for diffusion.
this occurs because the summation of the capillaries results in a larger diameter than any of the arteries, lowering pressure.
Term
What is the difference between systolic and diastolic blood pressure?
Definition
systolic blood pressure - the pressure when the heart is contracting
diastolic blood pressure (arterial side) - when the heart is relaxed.
Term
What is the regular blood pressure in homans?
Definition
120/80
120 - systolic
80 - measurement when heart is not contracting
Term
What is the evolution of the circulatory system?
Definition
1) undivided --> 1 atrium/ventricle. blood is oxygenated before going to body. Blood pressure is low (30/20). Low so that there is no fluid leakage.
2) Partially divided --> right/left atrium but only one ventricle. Potential for mixing of oxygenated/low oxygenated blood. Incorporates the lung (new organ). Useful for diving animals. Still 30/20
3) Completed divided (double circuit) --> right atrium/left atrium, right ventricle/left ventricle --> blood pressure from right ventricle to lungs = 30/20 (to ensure there's no fluid leakage)... blood pressure from left ventricle to body = 120/80
Term
What causes the heart sounds?
Definition
the closing of the heart valves and the backward "woosh" of the tiny bit of blood the is pushed backwards from it closing.

Closing of semi-lunar valves (aortic / pulmonary valves) = dub sound
closing of AV valves = lub sounds
Term
what are the names of the valves found in the heart and where are they? What causes them to close?
Definition
the atrioventricular valve - found between the atrium and the ventricle
the tricuspid valve - found between right ventricle and right atrium
the bicuspid valve - found between the left ventricle and the left atrium
Aortic valve - between left ventricle and aorta.
Pulmonary valve - between the pulmonary artery and right ventricle
when ventricles contract, AV close.
Term
What is the venous filling pressure?
Definition
When the atria has 0 pressure, because it has pumped all its blood into the ventricle, blood flows in from the vena cava. Most of the volume filled in ventricle comes from this pressure.
Term
what is myogenic? what cells of the body are myogenic?
Definition
myogenic means that it generates its own signal for contraction.
Myocardial cells are myogenic. Gut smooth muscles are also myogenic.
Term
Where does the electrical signal that stimulates heart beat stem from?
Definition
from the pacemaker (or the sinoatrial node (SA))
Term
What enables the myogenic abilities of the heart?
Definition
sodium leak channels.
Term
How is it, since the heart is myogenic, that the ventricles and atrium's do not contract at the same time.
Definition
All atria cells are connected. However, it is not spread easily to the ventricles.
there is only one place where the impulse can get to the ventricle and that is through the atrioventricular node (AV node). Signal slows down here.
the impulse travels down the middle of the heart, down the ventricular septum, into the bottom base of the heart.
it causes the "bottom up" signal.
Term
What is the autonomic nervous system's role in the circulatory system (with regards to the heart specifically)?
Definition
Parasympathetic - targets the SA node. inhibits heart activity through the release of acetylcholine.

sympathetic - stimulates the pacemaker + alter contraction strength by modifying ion currents. Epinephrine does this.
Term
What type of receptor senses blood pressure?
Definition
baroreceptor
Term
where are baroreceptors located?
Definition
in the carotid artery and just outside the heart, in the aorta.
Term
Autotrophs
Definition
organisms that make their own energy by using outside energy to make food (light energy)
Term
heterotrophs
Definition
eat a variety of substances (each other, autotrophs, etc) all animals are heterotrophs.
rely on autotrophs to create complex nutrients.
Term
how many ATP molecules are produced from a single glucose molecule? How many molecules of oxygen are used up at the same time?
Definition
1 molecule glucose + 6 molecules oxygen = 6 Carbon Dioxide + 6 h2o molecule + 36-38 ATPs
Term
What are synthetic enzymes?
Definition
Can make longer polymers. Production of body parts is done with synthetic enzymes. Uses dehydration reactions.
Term
What are hydrolytic enzymes?
Definition
Hydrolytic enzymes take longer polymers and break them down into the smaller monomers using hydrolytic enzymes. Uses condensation reactions.
Term
what are the advantages to extracellular digestion? How?
Definition
- cell interior is not exposed to digestive enzyme
- overall it is faster & more efficient.

how?
- more hydrolytic enzymes can be used
- more food can be digested/unit time
- more nutrients absorbed per unit time
Term
How quickly is the lining of the human stomach replaced?
Definition
over a three day period
Term
Why aren't cells lining the digestive system digested by the enzymes they secrete?
Definition
- protective coating also secreted
- damaged cells continually replaced by mitosis
- enzymes often excreted as zymogens (IE inactive forms)
Example: pepsin and pepsinogen
Term
which is the active form pepsinogen or pepsin?
Definition
pepsinogen is secreted by the stomach and is converted into pepsin by HCl.
Term
What are the types of digestive systems?
Definition
Cavities - found in sponges, cnidarians, flatworms. Single opening to exterior. cavity functions as digestive cavity/blood cavity.
Canals - all other animals. Two openings to exterior.
Term
Describe the alimentary canals (digestive tracts)?
Definition
- tubular, two openings
- food moves in one direction
- reduces mixing of digested / undigested material
- enzymes used more efficiently
- different stages occur simultaneously
- more food can be processed.
Term
What is the structure of the digestive tract tubes?
Definition
Exterior --> Serosa = support tissue
Interior to serosa --> 2 bands of smooth muscle that contract 'automatically' to propel food bolus (causes peristalsis) called Muscularis Externa... longitudinal/circular layers
interior to that is muscularis interna = smooth muscle layers at the very inside.
interior to that is the mucosa layer (composed of Ruga structures). Secretes mucus to lubricate, various chemicals to aid digestion.
interior to that is the submucosa (villus and microvillus) - contains capillaries and lymph vessels.
Term
Is the contraction of the stomach controlled by the nervous system? if not, what causes peristalsis?
Definition
peristalsis is caused by the contractions of muscularis externa smooth muscles when they are stretched from having bolus move past them.
muscularis externa = made of circular and longitudinal layer
Term
what is different between the villi and the microvilli in the stomach and the small intestine?
Definition
In the stomach villi project outwards.
in the stomach there are pits that secrete the enzymes and increase surface area. Contain mucosal cells that secrete a gastric juice (pepsinogen + HCl).
Stomach longitudinal/circular muscles are much larger/stronger!
Term
what is the name of the sphincter that separates the duodenum from the stomach?
Definition
the pyloric sphincter
Term
what is the difference between exocrine and endocrine glands?
Definition
endocrine glands - secretes substances into bodily fluids like blood
exocrine glands - secrete substances onto the surface of body or into a duct
Term
how are CHO molecules absorbed?
Definition
they are moved across the mucosal membrane using active transport.
they move directly into the blood.
Term
What is chyme?
Definition
food + gastric juice
Term
How are proteins absorbed?
Definition
broken down into amino acids.
moved across the membrane using active transport.
some occurs in the stomach, the rest in the duodenum.
pepsinogen(zymogen) is secreted in stomach and trypsinogen (zymogen) is secreted into the duodenum from the pancreas.
Term
what is the sphincter called where the bile and pancreatic juices come into the duodenum?
Definition
the sphincter of oddi
Term
How are fats absorbed? (explain the process from the breaking down to absorption)
Definition
Bile + pancreatic juices are added to chyme.
bile emulsifies fat droplets to form micelles.
Lipase from pancreas hydrolyzes fats in mycels to form glycerol + monoglycerides which diffuse directly into mucosal cells.
inside mucosal cells lipids are repackaged (by golgi) then released into lacteal LYMPH VESSEL (released into lymph vessel!)
Term
What is a lacteal?
Definition
a lymph vessel.
Term
what regions of the digestive system are under voluntary control?
Definition
Swollowing and defecation.
gut smooth muscle is myogenic. There are mechanically gated ion channels within it that open when smooth muscle expands.
Term
what is the parasympathetic and sympathetic nervous systems impact on the digestive system?
Definition
PNS - stimulatory. stimulates smooth muscle contraction in gut. inhibitory effects in blood vessels leading to the gut.
releases acetylcholine from post-ganglionic fibers

SNS - inhibitory mostly. Inhibits saliva, gut motility, and initiates vasoconstriction. IE reduces blood flow thru non-essential organs.
norepinephrine released from post-ganglionic fibers
Term
Which organ in the body has its own internal nerve network that can regulate activity within itself?
Definition
the gut.
Term
What are the major gut hormones?
Definition
Gastrin - targets stomach muscle/other mucosal cells. Stimulates motility, secretion of HCl, pepsinogen

CCK - targets gall bladder, pancreas, stomach. Stimulates secretion of bile, pancreatic juice. signals stomach to stop gastrin secretion. slows stomach motility/delivery of acidic chyme.

Secretin - targets pancreas. Stimulates secretion of pancreatic juice. HCO3 (bicarbonate) neutralizes acid in chyme.
Term
What is metabolism?
Definition
body processes that use or produce energy; occurs at multiple scales.
Term
What is metabolic rate
Definition
The rate at which body energy is used in metabolism.
Term
What occurs during the absorptive and post-absorptive states?
Definition
Absorptive - glucose is being stored as glycogen in liver and muscle and as triglycerides in adipose tissue. Emphasis on storage & synthesis.

post-absorptive - glycogenolysis --> glycogen is broken down into glucose in the liver... Gluconeogenesis occurs.
Term
What are glucose levels regulated at?
Definition
close to 90 mg/100 mL.
Term
What are the hormones that the pancreas secretes for glucose regulation? what other hormones can be involved in certain situations for gluconeogenesis/glycogenolysis ?
Definition
Insulin - secreted when blood glucose is above set point.
Glucagon - secreted when blood glucose is below setpoint.
epinephrine - during exercise
fasting - cortisol
body growth - Growth Hormone
Term
What hormone opposes the hormone epinephrine?
Definition
cortisol opposes the effects of epinephrine.
Term
At a whole body level, what is a change in metabolic rate seen as?
Definition
Altered oxygen consumption
altered CO2 production
Altered production of H+ & other byproducts
Altered heat production
Term
What are the advantages, disadvantages and consequences of being an ectotherm?
Definition
advantages: less food needed, lower body energy expenditures.
Disadvantages: Optimal temperature range is limited, need to cope with fluctuating body temperatures.
Consequences: limited body complexity. limited environmental range may be periods of inactivity.
Term
What is the name of the portion of the sperm that allows for the penetration of the ovum?
Definition
The acrosome.
Term
Where do the various hormones associated with the reproductive cycle come from?
Definition
from the brain-pituitary-gonadal axis
Term
What is FSH and what is LH?
Definition
They are gonadotropins

FSH = follicle-stimulating hormone is released from the anterior pituitary gland when GnRH is released from the hypothalamus. It stimulates germ cell development and sex steroid production in sertoli cells of gonads.

LH - Luteinizing hormone is released by the anterior pituitary when the hormone GnRH is released by the hypothalamus.
It stimulates the release of eggs in females; stimulates sex steroid production in the leydig cells of the gonads.
Term
What are the gonadotropins and what do they do?
Definition
gonadotropins regulate the synthesis of gonadal steroids.
gonadal steroids = androgens, estrogens (estrodyle) and progesterone.
Term
what is the precursor for estrodyle (and most sex hormones).
Definition
testosterone
Term
What is the precursor between cholesterol and androgens?
Definition
progesterone.
Term
Where is testosterone produced in the testes?
Definition
in the leydig cells. Stimulates spermatogenesis within testes (paracrine effect)
*also released in blood.
Term
what hormone(s) must be present to affect the leydig cells in testes?
Definition
leydig cells are stimulated by LH.
Term
What hormone(s) must be present to affect the sertoli cells of the gonads?
Definition
sertoli cells are stimulated by FSH.
Term
What are the different stages within the ovarian cycle?
Definition
follicular phase
- meiosis + mitosis going on
ovulation phase
- Release of ovum
luteal phase
- remnant conversion of follicle cell that has already released the ovum.
Term
What is the corpus luteum?
Definition
Corpus Luteum are modified cells that are engaged in additional hormonal production.
Term
What are the phases in the menstrual cycle?
Definition
Uterine (Menstrual) cycle -
day 1-6 = menstruation
day 7-14 = proliferative phase
day 15-28 = secretory phase
Term
Describe the hormonal cycle in the female reproductive system.
what happens when an egg is fertilized.
Definition
FSH stimulates oogenesis + estradiol secretion from follicular cells.
estrodial (E2) proliferates endometrium.
estrodial has positive feedback on hypathalamus + pituitary. Causes a surge of LH release to induce ovulation.
Corpus luteum secretes estrodial and progesterone (P). Estrodial and progesterone maintain the endometrium.
Estrodial (E2) and Progesterone (P) has negative feedback to inhibit FSH (another cycle).

In pregnancy:
after implantation in uterus, placenta forms and begins secreting hormones (chorionic gonadotropin [CG]) stimulates corpus luteum to keep producing estodial and progesteron.

if estrodial and progesterone fall than the endometrium will be shed.
Term
What hormone is required in order to maitnain pregnancy?
Definition
Progesterone from the corpus luteum is required to maintain gestation.
Term
What is it that pregnancy tests detect?
Definition
Pregnancy kits measure to degradation products that are created from chorionic gonadotropin (CG). This hormone is created 7-14 days after implntation.
Term
What is different in the reproductive cycle type of other animals?
Definition
primates have a menstrual cycle
other animals have an estrous cycle --> only difference is endometrium is not shed. everything else is the same.
benefit is they conserve energy.
Term
What is viviparity?
Definition
fertilized egg develops inside body, nourished from parent's body via a placenta. ** occurs in most mammals, a few fish.

they give "live" birth.
Term
do all mammals engage in viviparity?
Definition
No. only the platypus and echidna do not.
Term
What is oviparity?
Definition
Oviparity - fertilized egg develops outside body; nourished from yolk stores within egg.
occurs in most inverts, fish, amphibians, reptiles, birds & monotreme mammals (.e.g platyps)
Term
in oviparity, what serves to nourish the embryo?
Definition
the yolk sac. Directly impacts the type of embryonic development.
Term
What is Ovoviviparity?
Definition
fertilized eggs develop inside body; but not nourished by parent.
occurs in sharks + few other vertebrates & invertebrates.
In a few species, males may carry the developing eggs (seahorses, some frogs)
Term
What are the different stages of embryonic development?
Definition
1. fertilization
2. cleavage - produces mass of smaller cells thru mitosis
3. Gastrulation (establishment of germ layers: ectoderm, mesoderm, endoderm... becomes blastula (made up of blastomeres)) (Begins through a massive migration of cells towards the interor of the blastula, The dorsal lip forms at the vegetal pole as cells move inwards through the blastopore.)
4. neurulation - produces future nervous system
5. organogenesis - tissues become organized into differential cells
Term
Where do the initial steps of cleavage occur in embryonic development?
Definition
in the oviduct
Term
What is the archenteron?
Definition
The internal cavity that forms when the blastocoel gets filled and displaced during gastrulation.
Term
What does the blastopore eventually become?
Definition
eventually becomes the mouth (protostome) or the anus (deuterostome)
Term
who are the deuterostomes?
Definition
vertebrates, chordates, echinoderms
they will form the anus from the blastopore.
Term
the embryonic ectoderm, mesoderm and endoderm formed during gastrulation eventually become what ?
Definition
ectoderm - epidermis, central nervous system, neural crest
mesoderm - notochord, skeletal muscle, kidney tubule, rbc.
endoderm - digestive tube, pharynx, respiratory tube
Term
what are neural crest cells?
Definition
only found in chordates. neural crest cells migrate to form various adult structures: peripheral nervous system, adrenal medulla, cranial bones, jaw muscles
Term
What are somites?
Definition
Somites form in an anterior to posterior direction behind the brain and are formed of mesodermal cells.
they form vertebrae and trunk skeletal muscles
In terrest. vertebrates limb bones / muscles develop from cells that migrate out of somites into limb buds
Term
what adult structure is present where somites in embryonic development once were?
Definition
ganglia form where somites were present in embryo
Term
during development, differentiation is regulated by what?
Definition
- genetically controlled gene expression
- chemical signals (morphogens) between cells that alter expression
- concentration gradient of morphogens
Term
what do morphogens do?
Definition
promote the development of the animal body.
Term
how does the concentration of morphogens impact differentiation? What is the morphogen in vertebrates?
Definition
Called activin.
none = ectoderm resembling skin
low conc = blood like cells
mod conc = muscle cells
high conc = notochord like cells
very high conc = heart cells
Term
what is the major organizing center for the brain and head region during development. what stage does it begin in?
Definition
during gastrulation. Dorsal lip of the blastopore is a major organizing center for brain and head region.
Term
what gene codes the size of head in development?
Definition
the noggin gene. if too much noggin is expressed the head will be too large and organism will not be viable.
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