Unit 3 Flashcards
2 types of circulatory systems
open and closed
limitation of an open circulatory system
size of the animal
do open circulatory systems have blood?
no- have hemolymph
arteries carry blood ____ from the heart
away
veins carry blood ____ the heart
to
con of a closed circulatory system
metabolically expensive and under pressure so susceptible to hemorrhage
a two chambered heart (like in fish) have how many circuits?
one
- atria to ventricle
a three chambered heart has how many circuits? what is a limitation?
2 (2atria and 1 ventricle)
- deoxy and oxy blood mix
what kind of circulatory system do we as humans have
4 chambered (2 atria and 2 ventricles)
the heart is enveloped by what structure
pericardial sac
the ______ receives deoxygenated blood from the body
right atrium
what structures dump blood into the right atrium
superior and inferior vena cava
the _______ receives oxygenated blood from the lungs
left atrium
what structure dumps blood into the left atrium
pulmonary veins
the _____ ventricle receives blood from the right atrium
right
the right ventricle pumps blood into what structure
pulmonary trunk
the left ventricle pumps blood into the _______
aorta
are ventricles or atria thicker
ventricles- need to pump blood out of the heart
(LV is strongest)
the aortic semilunar valve prevents what
gravity from pulling blood back into the left ventricle
tricuspid valve between _____ and _________
right atrium and right ventricle
blood gets pumped into the lungs through the pulmonary trunk for
oxygenation
the cardiac cycle is one complete heartbeat that includes
1 contraction and relax
systole=
diastole=
contraction
relaxation
in diastole, what happens
heart is relaxed and blood enters the atria
atrial systole is when
atria contract and move blood to ventricles
what causes the chambers of the heart to contract and valves to close?
action potentials resulting in pressure changes
junctions between cells in the heart muscle are called
intercalated discs
what prevents cells from separating during contraction
desmosomes
what allows ions to pass freely from cell to cell and electrically couples adjacent cells
gap junctions
what kind of heart is innervated but continues to beat even without NS
myogenic
the human heart depolarizes and contracts _______ nervous system stimulation
without
what kind of cells rhythmically spontaneously depolarize in the heart
noncontractile (autorhythmic)
The ____ sets the pace of the heart, why?
SA node
fastest rhythym
atria contract in unison because of
gap junctions
autorhythmic cells have __ channels that allow Na+ channels to open at what rate
leaky
slow
the depolarization stage in cardiac muscle contraction is due to influx of what, at what rate
Na+, fast (huge influx)
the plateau phase of cardiac muscle contraction occurs after depolarization when there is _____ influx of ________
slow influx of Ca2+ channels
the impulse of action potentials is delayed at ______ , because ________
AV node, ventricles need to contract at different time than atria
baroreceptors detect
change sin BP
what released from medulla increases SA node firing rate
norepinephrine and epinephrine
the sympathetic nervous system _____ rate of SA node
- what does this lead to
increases
- enhances force and speed of ventricular contraction
the vagus nerve _____ heart rate
- part of what center
decreases
- cardioinhibitory
what are the three important sources of resistance in blood
- blood viscosity (more RBC)
- total blood vessel length (more length=more resistance)
- blood vessel diameter (larger diameter-less resistance)
pressure of circulating blood against the walls of blood vessels
blood pressure
what is the control center for extrinsic control of heart contractions
medulla
if blood pressure decreases, baroreceptors _______, which means ____ AP going from heart to medulla
stimulate less
less
the sympathetic NS is turned on by medulla to _____ BP
- the sympathetic nerves that innervate the ventricular walls do what
- the sympathetic nerves that innervate the blood vessels do what
- the sympathetic nerves in adrenal gland release _________ to increase heart rate
-increase
-stronger force contractions
-constrict vessels to increase BP
- epinephrine and NE
materials are exchanged in
- why
capillaries
- very thin walls
what creates the sounds we hear in the heart
valves closing
-1st lub: AV valve closing
-2nd dub: semilunar valve closing
A panda is drifting to sleep. One effect this has on the body is that there are increased signals sent along the vagus nerve. What will these signals directly lead to?
1. decreased SA node firing
2. decreased force of ventricular contraction
3. vasoconstriction
4. Release of epi and NE from adrenal gland
a. 1 and 2
b. only 1
c. 1, 2 and 4
only 1
adequate diet must satisfy 3 nutritional needs, which are
- fuel for cellular work
- organic materials for biosynthesis
- essential nutrients such as vitamins that animal cannot make for itself
______ are indigestible carbohydrates
Fibers
what are carbohydrates that humans can digest
sugar and starch
______ is needed by all body cells for energy
glucose
glucose comes from
carbs
proteins are made up of
amino acids
animals need a balance of the __ amino acids
20
_____ amino acids can be made by the body
______ amino acids cannot be made by the body and most be gotten from diet
nonessential
essential
lipids are ___ oils, and waxes
fats
many lipids are made up of _______ and ________
fatty acids
glycerol
lipids are the most energy dense, T or F
T
are lipids water soluble or non-water soluble
non water soluble (hydrophobic)
minerals are important for what
examples:
enzyme functioning
Na, K, Zn, Ca
animals with one way digestion have an advantage in that
can eat at any time (do not need to wait to poop to eat more)
which nervous system turns on the digestive system
parasympathetic (enteric)
two types of movement in the gut:
1.
2.
peristalsis
segmentation
which gut movement refers to mechanically mixing food and digesting it
segmentation
which gut movement refers to moving food through the GI tract
peristalsis
can an animal absorb molecules for which they do not have the enzyme to digest
no
the gut microbiome is an example of a __________ relationship, that does what
endosymbiotic
helps break down and synthesize molecules we cannot
order of the GI tract
headgut
foregut
midgut
hindgut
the hindgut is the _____ intestine
large
the headgut includes the _____ to ______
mouth to pharynx
what is the tongues function in digestion
helps bring food under the teeth to chew
(somatic-skeletal muscle)
what enzyme breaks down carbs in the mouth
salivary amylase
we have a monogastric stomach, meaning
simple (one way in and goes out the other)
peristalsis is stimulated by
parasympathetic NS (enteric)
what do the sphincters in the stomach do
trap door that is mechanically receptored to prevent stomach acid from going into esophagus or small intestine
what do rugae do in stomach
increase SA to expand the stomach for more food consumption and make more gastric juice
what is gastric juice made of
pepsin + HCl + mucus
pepsin is proteolytic, meaning
breaks down proteins
HCl’s role in digestion is
turn inactive pepsinogen to active pepsin
what stimulates gastric juice release
when stretching of the stomach when food goes in occurs, gastrin is released (stimulates more gastric juice release)
gastrin is a
hormone
(positive feedback)
what kind of cells in gastric pit release HCl
parietal cells
what kind of cell in gastric pit release pepsinogen
chief cells
gastrin stimulates what 2 kinds of cells in the gastric pits
chief and parietal
Delta cells in gastric pit is released when
-bc
no digestion occurs
- bc it inhibits acid secretion (HCl)
why can we not digest cellulose
plants have a cell wall (made of cellulose) and we do not have the enzyme to digest it (cellulase)
cows are _________, meaning they have a 4 chambered stomach to help digest cellulose
ruminants
why do cows constantly chew
regurgitate and chew on cud to further break down fibers to help microbial life digest the cellulose
where is bile produced? stored?
produced in liver
stored in gallbladder
what is the function of bile
emulsify fat into small droplets to not come and make a big ball
- decrease attraction to each other
what stimulates the pancreas to release bicarbonate to neutralize stomach acid in small intestine
secretin
secretin is released to do what
stimulates the pancreas to release bicarbonate to neutralize stomach acid in small intestine
bicarbonate symbol
HCO3-
fat digestion ends with what
the fat is to large to go into blood stream, so first goes into the lymphatic capillary 1st
During absorption in digestion
a. glucose is absorbed through
b. amino acids are absorbed through
c. lipase (fats) are absorbed through
a and b= blood capillary
c= lymphatic capillary
how exactly is the mechanism where glucose is absorbed through the intestines
Na/K pump keeps Na low in the cell so that Na/glucose transporter can move glucose up its concentration gradient w GLUT-2 transport protein
digestion of fat in the bile is from the enzyme called
- which then form
lipase
micelles
major function of the colon (large intestine)
recover water that has entered the canal ( becomes more solid through this tract)
control center for hunger is located where
hypothalumus
what is the only appetite stimulant
ghrelin
what is an appetite suppressant
leptin
Having more fat in the body means having
- higher or lower Leptin
higher
Having more fat in the body means having
- higher or lower ghrelin
lower
leptin is secreted by ____ cells
adipose (fat)
is it more important to gain or loose weight
gain
osmoconformer
maintain an internal environment which is isotonic to their external environment
osmoregulators
maintain osmolarity differently in internal vs. external environment
water goes from an area of
high to low water
(low to high osmolarity)
how do osmoregulators make sure their fluids stay within a narrow range
kidney
transport urine from kidneys to urinary bladder
ureters
transports urine out of the body
urethra
where are nephrons located in the kidney
renal cortex
urine composition changes based on what
the blood needs to get rid of
what does dilute urine mean
the body is hydrated and doesn’t need to retain the water
water in urine consists of 2 parts which are
- obligatory amount of water to leave body with solutes
- additional depending on hydration levels
this waste in urine is from amino acid breakdown
urea
kidenys function with a ____ mechanism
a. countercurrent
b. isocurrent
a. countercurrent
the loop of Henle has two parts which are
descending limb and ascending limb
what structure of the kidney is blood actually filtered in
nephron
3 main events in urine formation
- which one is always first
- glomerular filtration (always first)
- tubular reabsorption
- tubular secretion
blood cells do not go through the walls of glomerular capsule because
it is fenestrated: tiny holes (pores)
- allows stuff to be exchanged but not big enough for blood to go through
glomerular filtration is a _______ process
a. active
b. passive
b. passive
what CAN pass through capillary walls during glomerular filtration
glucose, ions, and amino acids
what CANNOT pass through capillary walls during glomerular filtration
proteins (WBC, RBC)
after the glomerular filtration in the bowman’s capsule, where does filtrate go next
proximal convoluted tubule (PCT)
all nephrons have a ___ blood supply
rich
in the PCT, the aquaporins are _______ open
always
two routes of tubular reabsorption, they are
paracellular
transcellular
what is transcellular tubular reabsorption
item passes across the cell
what is paracellular tubular reabsorption
solutes can pass between the adjacent cells because of leakiness
Na+ uptake in the PCT is driven by what
gradient established by the Na+/K+ pump
glucose uptake in the PCT is driven by
secondary active transport
(Na/Glucose symporter)
if there is too much glucose filtered, what happens
to a certain point there are not enough proteins for uptake, so you excrete it
after the PCT, where does filtrate go next
loop of Henle
what does the loop of Henle provide the capacity for
- why is it important
to make hyperosmotic urine (concentrated)
- to conserve water in bodies if live on land
the descending limb of the loop of henle is permeable to
only water
the ascending limb of the loop of henle is permeable to
ions
the _______ limbs ions draw water out of the ________ limb
ascending, descending
the ascending limb is able to influence the descending limbs contents because
they share an interstitial fluid
in the loop of Henle, where does the filtrate concentration reach its highest
at the bend of the loop (bottom)
filtrate is at its mots dilute in the loop of Henle when
it leaves the nephron loop
when Na+ is moved out of loop of Henle in ascending loop, is it active or passive transport
active
which vein (blood supply) runs alongside the loop of Henle?
- in what direction
vasa recta
- countercurrent (opposite)
the _________ reclaims the water that leaves the loop of Henle
vasa recta blood
a longer loop of Henle means ____ concentration gradient
greater
- can make more concentrated urine
what is the function of aldosterone
increases the Na+ absorbed back to the blood, which means more water follows (back into the body from filtrate)
what senses the Na content of the filtrate
chemoreceptors in macula densa
what senses the BP in afferent ateriole
granular cells
what is the main mechanism for raising BP
RAAS
- renin, angiotensin-aldosterone mechanism
how is the RAAS pathway for raising BP activated
macula densa cells chemoreceptors sense when filtrate Na+ is too low (meaning not a lot of water–> meaning low volume–>low pressure)
____ is an enzyme released by the kidney to facilitate the conversion of angiotensinogen into angiotensin I
Renin
What factors stimulate renin secretion
- decreased BP
- decreased Na+ delivery to macula densa
- increased sympathetic NS signals
angiotensin I is converted into angiotensin II by
ACE
when angiotensin II is made by ACE, what are some effects it creates
- stimulates released of ADH from posterior pituitary
- hypothalumus signals more thirst
- adrenal cortex is signaled to secrete more aldosterone
renin is released by the ________ cells in the kidney
granular
ADH is released by the ________
posterior pituitary gland
ADH is released when an _____ in blood osmolarity or a _________ in blood volume is detected
increase
decrease
what effect does ADH have
causes principal cells of collecting ducts to insert aquaporins into apical membrane
ADH causes ____ cells to insert more ____ into collecting duct
- what is the result
principal
aquaporins
- more water reabsorption into the body
as ADH levels __________, water reabsorption increases
increase
frequent urination and excessive thirst are symptoms of
lack of ADH or no response to ADH
why does ADH make your urine more concentrated
ADH allows body to reabsorb more water, so urine comes out with less water
ADH activity is ____ of Na+
independent
what is the main job of the loop of Henle
establish a medullary gradient that influences water reabsorption
what is the main function of the juxtaglomerular complex
maintain BP
how is BP increased
increase Na reabsorption, increased water reabsorption
dehydration leads to ____ ADH secretion
increased
Which cells in the ascending limb have chemoreceptors that sense Na content in the filtrate
Mácula densa
The mácula densa is located where
Ascending limb
(Detects Na levels)
Granular cells are sensitive to what
Stretch by BP in aferentes arteriole
What increases active transport of Na out of cell to filtrate when blood volume is low
Aldosterone
Three pathways to renin release by granular cells
- Direct stimulation of granular cells by sympathetic NS
- Activated mácula densa cells when filtrate Na is low (chemoreceptors)
- Reduced stretch of granular cells (so need to increase BP to increase stretch)
What is the main mechanism to increasing BP
Renin-angiotensin-aldosterone mechanism
What makes angiotensinohen into angiotensin 1
Renin
What makes angiotensin 1 into angiotensin 2
ACE
Which is the correct order
a. Angiotensin 2–angiotensinogen—angiotensin 1
b. Angiotensinogen—angiotensin 1– angiotensin 2
B
