4 - STRUCTURE AND FUNCTIONS OF SYSTEMS Flashcards
what are the (4) main types of tissue?
epithelial (skin or internal organ covering)
connective (bone, cartilage, blood)
nervous
muscle
differentiate between negative and positive feedback
negative feedback: bringing conditions back to their normal or homeostatic function
positive feedback: an action that intensifies a condition so that it is driven further beyond its normal limits (e.g., labor contraction, lactation, or sexual orgasm)
how many lobes are in your right and left lung?
right lung: 3 lobes
left lung: 2 lobes
what is the membrane surrounding the lungs called? what are it’s 2 layers called?
pluerae, a membranous cover
inner layer: visceral pleura
- lines the lungs
outer layer: parietal pleura
- lines the chest cavity aka thoracic cavity
in between is the interpleural space
what is the diaphragm? what role does the diaphragm play?
a muscle that’s the lower border of the thoracic cavity. separates the thoracic cavity from the abdominal cavity
when you inhale, the diaphragm flats, allowing your chest cavity/lungs to expand
when you exhale, the diaphragm relaxes and pushes back upward which causes your chest and lungs to shrink in size, forcing air outward
what type of cell lines the respiratory tract? what do they do? where are these cells found?
respiratory epithelium
they produce mucus to moisten and protect our airways
the cells also have cilia which sweep away trapped pathogens and particles
found everywhere in the respiratory tract except the pharynx and larynx
list the structures of the respiratory tract in order
mouth/nose
pharynx
larynx
trachea
bronchi
bronchiole
alveoli
in the nose/mouth, what cell secretes mucus?
goblet cells (part of the respiratory epithelium)
what role does the pharynx play?
serves as the passageway for air and food (to the respiratory system and the digestive system)
what happens if a piece of food gets stuck in your windpipe?
the larynx will trigger the cough reflex to clear your airways
describe the structure of the trachea
a tube lined with c-shaped cartilage rings
what’s the epiglottis?
a structure covering the trachea, preventing solids/liquids from accidentally entering. when we breathe air, the epiglottis remains open so air can pass thru
what are alveoli? describe them
where gas exchange occurs between the respiratory and circulatory system
small, grape-like clusters
have a thin layer of cells, surrounded by capillaries. this layer serves as the interface between the respiratory system and the circulatory system
coated with surfactant, a liquid covering that reduces the surface tension, preventing H2O from collapsing the alveoli
what role does surfactant play in the respiratory system?
is a coating the covers alveoli, preventing it from collapsing as we inhale and exhale
what are the (2) major functions of the respiratory system?
internal respiration
external respiration
(both work together to get oxygen from the outside environment into our body’s cells and CO2 out our blood and exhaled)
differentiate between internal and external respiration
external respiration
- entry of air into lungs
- gas exchange between alveoli and blood (CO2 from blood to lungs to be exhaled; O2 from lungs to blood) – supplies blood with oxygen
internal respiration
- gas exchange between blood and cells (CO2 from cells to blood to be taken away to lungs; O2 from blood to cells) – supplies cells with oxygen
- intracellular respiration processes
how does gas exchange between the alveoli and the capillaries occur (in the respiratory system)
via simple diffusion (no transport proteins needed!!): gases like oxygen and carbon dioxide can simply diffuse across the thin alveoli membrane
how does CO2 move in the bloodstream? (how’s it transported?)
considered bulk flow!!: volumes of fluid move from an area of higher pressure in a capillary bed to an area of lower pressure in the tissues via filtration
primarily transported in the plasma, the liquid portion of blood in the form of bicarbonate (HCO3-)
most CO2 in the blood gets combined with water to form carbonic acid which then dissolved into bicarbonate and H+ ions. this reaction is catalyzed by enzyme, carbonic anhydrase. it occurs in red blood cells
can also be transported as it is (CO2). it can mix directly with the plasma as a gas or can bind with hemoglobin inside of the RBCs, forming carbaminohemoglobin
how does oxygen move in the bloodstream? (how’s it transported?)
primarily transported in the blood via hemoglobin
this is considered bulk flow: volumes of fluid move from an area of higher pressure in a capillary bed to an area of lower pressure in the tissues via filtration.
how do gases in the blood get to the cells of our body?
oxygen will be unloaded by the hemoglobin and diffuse out of the red blood cells across the thin walls of our blood vessels thru any interstitial fluid, finally entering the cell by diffusing across their membrane
CO2 follows the opposite path. it diffuses out of the cell, across the membrane, thru the interstitial fluids, and across the blood vessel walls where they can be transported by red blood cells as bicarbonate
what part of the brain controls respiration? what does it do specifically and how?
medulla oblongata
makes sure you’re always breathing, whether it’s conscious or unconscious
will also adjust breathing rate depending on oxygen needs of the body. this is done thru chemoreceptors which monitor levels of certain chemicals in the blood. the medulla specifically looks for H+ ions in the bloodstream. this is because when CO2 is transported in the blood, the process produced H+ ions. so when there’s lots of CO2, there will be lots of H+ ions. the medulla will signal the diaphragm contract so oxygen can be brought in and then CO2 exhaled.
some chemoreceptors also looks at concentrations of oxygen and CO2
an increase in H+ or CO2 will cause an increase in breathing rate. High blood oxygen partial pressure would cause a decrease in breathing rate.
how are fish able to survive and get oxygen without being exposed directly to air?
gills are highly folded surfaces that provide a large surface area across which gas exchange can occur
to get oxygen from the water, fish use something called countercurrent exchange. as a fish swims thru water, water flows over the gills in the opposite direction of the blood that is flowing thru the fish. as the water and blood flow past one another, the oxygen that is dissolved in the water, diffuses into the bloodstream, replenishing the oxygen levels in the fish’s blood
this process occurs many times due to the large surface area which is how fish are able to survive from the oxygen gained from the countercurrent exchange
countercurrent exchange maximizes diffusion of oxygen into the blood and carbon dioxide into water
why do fish die when they’re taken out of water?
water helps keep their gills separated, maintaining the large surface area
when removed from the water, their gills collapse onto one another, reducing the surface area. leads to death due to insufficient oxygen intake
** FISH DO NOT HAVE LUNGS!!
describe hemoglobin
a protein that functions to transport oxygen in our bloodstream
has 4 polypeptide subunits. each of these subunits contain an Iron (Fe) atom which is critical to the function as Iron is what binds to the oxygen
describe cooperativity in hemoglobins
in cooperativity, a molecule has multiple binding sites. when oxygen binds to one site, it increases the affinity for the next oxygen to bind.
so, each oxygen that binds makes it easier for the next one to bind
note that hemoglobin can bind up to 4 oxygens (1 for each iron atom)
the reverse is true as well! when you remove an oxygen from hemoglobin, it becomes easier for the next oxygen to come off
what is myoglobin?
used to transport oxygen to and from the cell in muscles
equivalent of hemoglobin
has a different binding affinity from hemoglobin
describe the structure of hemoglobin
has 4 heme groups: each with an iron atom in the centre surrounded by a porphyrin ring. the iron is able to form up to 6 bonds, one of which is to the oxygen
note that heme is a prosthetic group (a non protein, iron, attached to a protein)
what does it mean when the oxygen-hemoglobin association curve has been shifted to the right?
leads to reduced affinity between oxygen and the hemoglobin. hemoglobin will release oxygen more easily – due to increased oxygen demands, the hemoglobin will be less stingy!
so, a left shift means increased affinity. hemoglobin will hold onto oxygen more tightly. this is when cells have less oxygen need
what (5) factors causes the oxygen-hemoglobin association curve to shift right? describe these factors
“CADET - face right”, an increase in the following will cause the curve to shift right
CO2: an increase in CO2 = an increase in cellular respiration = oxygen being used up and supply needs to be replenished
Acid: increased CO2 levels = more acid = hemoglobin is more likely to release oxygen due to conformational change induced by increased acidity (acidic = low pH). this conformational change will preferentially bind to CO2
2,3 DPG: a metabolite that gets consumed whenever oxygen is present. but if oxygen isn’t present, 2,3 DPG builds up so it’s presence indicates lack of oxygen in tissue
Exercise: it consumes oxygen and produces CO2 during its process
Temperature: high temp = high metabolic rate = consuming more oxygen and cells will demand more of it than usual
define thermoregulation
control of exchange of heat with the environment
differentiate between ectotherms and endotherms
ectotherms (COLD-BLOODED)
- obtain body heat from the environment
- include invertebrates, amphibians, reptiles, and fish
endotherms (WARM-BLOODED)
- generate their own body heat and have a much higher basal metabolic rate (BMR) than ectotherms
what are cnidaria?
includes soft-bodied stinging animals such as corals, sea anemones, and jellyfish
how does respiration work in cnidaria?
direct with the environment!!
have large surface areas and every cell is either exposed to the environment or close to it → simple diffusion of gases directly with outside environment
(flatworms and some small animals also exhibit this type of respiration)
what are annelids?
include earthworms, polychaete worms, and leeches
members of the group are to some extent segmented, in other words, made up of segments that are formed by subdivisions that partially transect the body cavity
how does respiration work in annelids?
mucus secreted by earthworms provides a moist surface for gaseous exchange via diffusion
the circulatory system brings oxygen to cells, and waste products back to the skin for excretion
what are arthropods?
includes such familiar forms as lobsters, crabs, spiders, mites, insects, centipedes, and millipedes.
distinguishing feature of arthropods is the presence of a jointed skeletal covering composed of chitin (a complex sugar) bound to protein
how does respiration work in arthropods?
series of chitin-lined respiratory tubules called trachea that open to the surface via openings called spiracles, through
which oxygen enters and carbon dioxide exits
oxygen carriers such as hemoglobin are not needed due to the direct distribution and removal of respiratory gases between the air and body cells
the moistened tracheal endings ease the rate of diffusion
DIFFERENT FOR SPIDERS: they have book lungs that are stacks of flattened membranes enclosed in internal chambers
describe the structure of lungs
these are invaginated structures made of two sub-portions: the left lung and right lung
the left lung is smaller and consists of 2 lobes, while the right lung is made of 3 lobes
left lung is smaller to accommodate the heart, which is also on the left side of the chest
lungs have a membranous cover known as the pleurae, which have two pleura layers: the visceral and parietal pleura. the space in between these two layers is the intrapleural space
describe the pressure in the intrapleural space (space between the two membranes of the lung) and lungs as we inhale
has negative (lower) pressure relative to the atmosphere. if stabbed, air rushes in and causes the lung to collapse
the pressure of this intrapleural space decreases as we inhale: as the diaphragm contracts, the lung cavity opens up, and this increase in volume equates to a decrease in pressure
similarly, the pressure inside of the lungs also changes. as we inhale, the volume of the lungs as expands as the diaphragm drops. by doing so, we create a negative pressure relative to the atmosphere, causing air to rush in
considered bulk flow!!: the lungs increase in volume and decrease in pressure, leading to a bulk flow of air into lungs
describe the haldane effect?
it describes how the deoxygenation of blood increases its ability to carry CO2
when hemoglobin is saturated with oxygen, its capability to hold CO2 is reduced. essentially, we pick up CO2 in the tissues where it’s generated, and get rid of it at the lungs and exchange it for oxygen.
hemoglobin without oxygen acts as a blood buffer by accepting H+ → this reduced hemoglobin has a higher capacity to form carbaminohemoglobin, rather than the oxygen carrying kind, explaining how the Haldane Effect occurs.
in summary, the Haldane Effect relates how [O2] is affecting hemoglobin’s affinity for CO2 and H+
describe the bohr effect
when tissues are high in CO2, and therefore high in H+, tissues are not getting a lot of oxygen, and we want to oxygenate them
as a result, the hemoglobin once near the tissues is exposed to the higher CO2 and H+ levels, and changes its structure to the reduced form. this reduced form now releases its O2 to the deoxygenated tissues, and preferentially binds to CO2.
at the lungs, the CO2 wants out and is
released. the H+ concentration is also lower here due to bicarbonate being converted back into CO2 for release. at this point, hemoglobin will change back to its non-reduced state that preferentially binds to oxygen, which holds it more tightly under these conditions.
the Bohr Effect, therefore, relates to how CO2 and H+ affect hemoglobin’s affinity for O2.
hemoglobin binding affinity decreases under conditions of low pH (high CO2/high H+) which leads to oxygen loads released by hemoglobin since both oxygen and H+ compete for hemoglobin binding sites
what is emphysema?
a disease marked by destruction of the
alveoli
what effects does smoking have on the respiratory system?
smoking can damage the cilia of respiratory cells and allow toxins to remain in the lungs
mucus produced by goblet cells increases, and lungs have a decreased means of moving mucous out, leading to a persistent yet unproductive cough
can lead to bronchitis, emphysema, and lung cancer
differentiate between respiratory acidosis and alkalosis
Respiratory Acidosis
- results from inadequate ventilation; we don’t clear enough CO2 and it builds up, so more H+ is formed, lowering the pH
Respiratory Alkalosis
- results from breathing too rapidly (hyperventilation); we are losing CO2 too quickly, so H+ and HCO3- start combining to form more CO2, and the pH begins rising
differentiate between metabolic and respiratory acidosis/alkalosis
important to understand that metabolic acidosis and alkalosis are not due to breathing issues - you may alter breathing to compensate, but the cause is not breathing related.
differentiate between the fetal and adult oxygen-hemoglobin dissociation curve
fetal hemoglobin curve is shifted left of the adult hemoglobin curve because the structure has a higher binding affinity in order to grab O2 from maternal blood
differentiate between the oxygen dissociation curve of myoglobin and hemoglobin
myoglobin of muscle has a hyperbolic curve since the structure doesn’t participate in allosteric cooperative binding due to the single subunit shape
myoglobin also saturates quickly and releases in situations of very low oxygen “emergency situations”
what has a greater affinity for hemoglobin than oxygen?
carbon monoxide (CO) has a 200x greater affinity for hemoglobin than oxygen does [forms carboxyhemoglobin] and requires administration of pure oxygen to displace it once bound
differentiate between respiration in mammals and birds (avian)
due to the unique anatomy of birds, respiration is both continuous and unidirectional
air sacs allow birds to exchange gas during both inhalation and exhalation — oxygen rich incoming air is first stored in air sacs before entering lungs for exhalation, so it is not mixed with the deoxygenated outgoing air
In mammalian respiration there is tidal breathing — we breathe in and out through the same tubing, inhibiting gas exchange during exhalation. Deoxygenated air is mixed with
some fresh air during inhalation, thus some of it
is re-inhaled. Much less efficient than birds.
what is tidal volume? (Vᴛ)
the volume of air that is normally inhaled or exhaled in one quiet breath
what is inspiratory reserve volume (IRV)?
the maximum volume of air that can be inhaled after a normal tidal volume inhalation
what is expiratory reserve volume (ERV)?
the maximum volume of air that can be exhaled after a normal tidal volume exhalation
what is residual volume (RV)?
the amount of air remaining in the lungs after maximum exhalation
air that cannot be exhaled
what is vital capacity (VC)?
the maximum volume of air that can be exhaled after a maximum inspiration
expressed as IRV + VT + ERV
what is inspiratory capacity (IC)?
the volume of air that can be inhaled after a normal exhalation
expressed as VT + IRV
what is functional residual capacity (FRC)?
the volume of air remaining in the lungs after normal exhalation
expressed as ERV + RV
what is total lung capacity (TLC)?
the maximum amount of air that the lungs can accommodate
expressed as IC + FRC
Give the sequence that correctly describes the order of valves that blood passes through as it flows through the heart?
Tricuspid valve → Pulmonary valve → Mitral valve → Aortic valve
what is pericardium? describe it
a double layered sac that envelopes the heart
the outer layer: fibrous pericardium
- protects the heart and holds it in place
the inner layer: serous pericardium
- consists of 2 layers with space in between: parietal, pericardial cavity, visceral
- space (pericardial cavity) is filled with fluid that lubricates the heart as it pumps, preventing friction between the layers
what are the (4) chambers of the heart? where are they in relation to each other?
right atrium / left atrium
right ventricle / left ventricle
atriums on top
ventricles below
what separates the 4 chambers of the heart?
upper and lower chambers are separated by valves
the right and left sides are separated by the septum, a muscular wall
which chambers carry oxygenated blood and which carry deoxygenated blood? what does this mean?
the right side carries deoxygenated blood which needs to be oxygenated SO they get pumped to the lungs
the left side carries oxygenated blood (fresh from the lungs) which is needed by tissues of the body
describe the pressures experienced by the blood in the different chambers of the heart? why do they differ?
the blood in the atria (upper chambers) experiences low pressures as they just need to be pumped to the ventricles (lower chambers)
the blood in the ventricles experiences much higher pressure as they need to be pumped to different organs and tissues in the body
why do ventricles of the heart have thicker walls than the atria?
the blood in the ventricles experiences much higher pressure as they need to be pumped to different organs and tissues in the body - hence, thicker walls to pump the blood with more force
what is the purpose of valves in the heart?
to prevent the backflow of blood
the valves only open under pressure and then close
what are the (4) valves in the heart? where are they?
tricuspid: between the right atrium and right ventricle
pulmonary: between right ventricle and pulmonary arteries
mitral (bicuspid): between the left atrium and left ventricle
aortic: between the left ventricle and aorta
differentiate between arteries and veins
veins carry blood to heart (deoxygenated)
arteries carry blood away from the heart (oxygenated)
the pulmonary circuit is an exception
- pulmonary veins carry oxygenated blood
- pulmonary arteries carry deoxygenated blood
what is the aorta?
a really thick muscular artery that distributes blood from the left ventricle to the rest of the body
really strong: can withstand high pressure of blood pumped from the heart
how many heart chambers do fish have?
2 heart chambers: 1 atrium and 1 ventricle
how many heart chambers do amphibians have?
3 heart chambers: 2 atria and 1 ventricle
how many heart chambers do reptiles have?
3 heart chambers: 2 atria and 1 ventricle
how many heart chambers do birds have?
4 chambers: 2 atria and 2 ventricles
what’s the exception to the heart chamber rule for reptiles?
normally, reptiles have 3 heart chambers (2 atria and 1 ventricle) BUT
alligators and crocodiles have 4 heart chambers
what are the (2) pathways of the circulatory system?
pulmonary: blood pumped to and from lungs
systemic: blood pumped to and from tissues of the body
what are the steps of pulmonary circulation?
blood is pumped from the right ventricle - thru the pulmonary valve - to the pulmonary arteries
blood gets reoxygenated at the capillaries/alveoli of the lungs where gas exchange occurs
blood travels back to the heart’s left atrium via pulmonary veins
where in the body does blood have the lowest oxygen concentration?
pulmonary artery
blood has been depleted of all its nutrients and oxygen by the rest of the body by the time it has reached the pulmonary artery
where in the body does blood have the highest oxygen concentration?
pulmonary vein
blood was just supplied with fresh oxygen from the lungs
what are the steps of systemic circulation?
left atria contracts and pushes blood thru the mitral valve to left ventricle
left ventricle contracts (very strong) and blood travels thru the aortic valve to aorta
blood from aorta travels to entire body
blood reaches the capillaries (capillary beds) in the tissues of the body. the cells surrounding the capillaries absorb the nutrients and oxygen from the arterial end and unload carbon dioxide and waste into the venous end of the capillaries
veins carry the blood back to the superior and inferior vena cava which empty it into the right atrium
blood from the right atrium goes thru the tricuspid valve into the right ventricle
what are the (2) phases to heart contraction?
systole: when the heart contracts, squeezing out blood
diastole: when the heart relaxes after a contraction
what starts a heart contraction? what initiated our heartbeat and how is that electrical signal spread?
a group of cells called the sinoatrial node (aka SA node aka pacemaker) which can generate their own electrical impulse
they initiate our heartbeat by depolarizing and spreading an electrical signal. the electrical signal spreads smoothly from one cardiac muscle cell to another
connecting these cardiac muscle cells at the intercalated discs are gap junctions which allow ions to flow smoothly from one cell to another - allows the electrical signal to move in a coordinated way
the electrical signal begins at the SA node. this electrical signal causes both of the atria to contract as it spreads thru out the walls of the atria
the electrical signal arrives at the AV node (atrio ventricular node). there’s a bit of delay to make sure the blood has been completely ejected from the atria to fill the ventricles.
the electrical signal will travel from the AV node down thru cells called the Bundle of His (which is in the septum between the lower ventricles)
when the electrical signal hits the bottom, it branches upwards and outwards thru the cell walls of the ventricles via Purkinje Fibers. this causes both ventricles to contract simultaneously
what are the (6) phases of the cardiac cycle mapped out on the electrocardiogram - the heartbeat monitor thingy?
P-wave: represents the electrical signal of the atria contracting.
after the P-wave
QRS-complex: big spike due to the ventricles contracting/depolarizing (which hides the atria repolarizing)
after the QRS-complex
T-wave: represents the ventricles repolarization to prepare for another contraction
after the T-wave
REFER TO DIAGRAMS
describe this relationship: cardiac output = stroke volume x heart rate
cardiac output: volume of blood that gets pushed out of the ventricles in 60 seconds
stroke volume: volume of blood that gets pushed out of the ventricles per contraction
heart rate: number of contractions your heart has per minute
describe this relationship: stroke volume = end diastolic volume - end systolic volume
the reason for this formula is because when ventricles contract, they don’t push out 100% of the blood they hold
stroke volume: volume of blood that gets pushed out of the ventricles per contraction
end diastolic volume: how much blood in the ventricle before the contraction
end systolic volume: how much blood in the ventricle after the contraction
describe this relationship: blood pressure = cardiac output x systemic vascular resistance
blood pressure: pressure exerted by circulating blood onto the vessel walls
cardiac output: volume of blood that gets pushed out of the ventricles in 60 seconds – the more blood pushed out of the heart per minute, more pressure onto walls
systemic vascular resistance: measure of resistance to flow of blood. influenced by diameter of blood vessels and blood viscosity
what factors influence systemic vascular resistance?
influenced by diameter of blood vessels and blood viscosity
systemic vascular resistance: measure of resistance to flow of blood
which type of blood vessel is the thickest and why?
arteries
they must withstand the highest pressure to pump blood to the rest of the body
describe the pathway blood travels in terms of blood vessels
from the heart
arteries
arterioles
capillaries (where gas exchange occurs)
veinules
veins
describe the composition of arteries (its layers)
FROM OUTERMOST TO INNER!!!
connective tissue layer which strengthens the artery and allows it to attach to nearby tissue
thick muscular layer of smooth muscle. it contracts/relaxes to regulate the diameter of the artery. also allows artery to withstand the high pressure of blood being pumped with a lot of force from the heart
elastic layer. gives the artery flexibility to stretch and withstand the pressure of the blood
layer of endothelium cells. allows the blood to flow easily
TO SUMMARIZE, arteries are large, muscular, and elastic
describe the composition of arterioles (its layers)
connective tissue layer which strengthens the arteriole and allows it to attach to nearby tissue
smooth muscle layer in between (thinner here than in the artery but for its proportion, arterioles have a thicker one… hence able to exert more control with diameter and blood pressure here)
inner layer of endothelial cells. allows the blood to flow easily
describe the composition of capillaries (its layers)
ONLY ONE LAYER
a single-celled layer of endothelium – allows for oxygen and nutrients and waste to diffuse easily
what are the (2) types of blood pressure forces at work in the capillaries? describe them and how they work together
hydrostatic: pressure from the fluid inside the vessels pushing up against the blood vessel wall - wants to move things out of the capillaries
oncotic: works in the opposite direction. pressure from the proteins in the blood attracting water from outside the vessel. it pulls things like extra fluids, waste product, and CO2.
hydrostatic pressure and oncotic is present in every part of a blood vessel. but the amount of each varies.
in the arterial side of the capillaries, hydrostatic pressure is high = net filtration of fluids and small molecules get pushed out into the tissue space
note that oncotic pressure stays the same
in the venous end, hydrostatic pressure is lower than oncotic = net movement back into the capillaries = reabsorption
what are precapillary sphincters?
rings of muscle that contract to clamp down and block blood vessels or relax to let blood flow more easily
can control where blood goes. this selective blood flow is helpful to stop blood for going to certain tissues depending on body’s needs
describe the composition of veinules (its layers)
outer layer of thin connective tissue
thin muscle layer in the middle
endothelium layer on the inside
describe the composition of vein (its layers)
connective tissue outer layer
muscle layer (thin because pressure is very low here)
elastic layer
inner endothelium layer
how do veins make sure blood reaches the heart considering the low pressure it has?
one way valves that prevent back flow backwards due to gravity
also assisted by skeletal muscle contractions to propel the blood forward
blood will eventually reach the superior and inferior vena cava
