circulatory and respiratory system Flashcards
cycle of blood flow
blood is pumped into the aorta which branches into a series of srteries
the arteries branch into arterioles and then into micrscopic capillaries
exchange of gases, nutrients, and cellular waste occurs via diffusion across capillary walls
the capillaries than converge into venules and eventually into veins, which carry deoxygentated blood backtoward the heart
from the heart the deoxygentated blood returns to the heart to be pumped throughout the body once more
aorta
the main artery of the body, supplying oxygenated blood to the circulatory system. In humans it passes over the heart from the left ventricle and runs down in front of the backbone.
superior vena cava
large vein carrying deoxygenated blood into the heart
carrying blood from upper body, head, arms
inferior vena cava
a large vein carrying deoxygenated blood into the heart.
carries blood from the lower body
heart structure
driving force of circulatory system
its right and left valves can be viewed as 2 separate pumps- right side of the heart pumps deoxygenated blood into pulmonary circulation (toward lungs)
left side pumps oxygentated blood into systemic circulation (throughout body)
has 2 upper chambers called atria
2 lower chambers called ventricles
atria are thin walled
ventricles are muscular
ventricls
lower chambers of the heart
are muscular
left ventricle is more muscular than right because it is responsible for generating the force that propels systemic circulation and because it pumps against higher resistance
in patients with increased systemic resistance, the left ventricle can become hypertrophied (enlarged) which over time can lead to congestive heart failure and other caridovascular diseases
atria
upper chambers of the heart
thin-walled
blood retunring from the body first flows through the right atrium anf then through the tricuspid valve into the right ventricle, and finally through the pulmonary semilunar valve into the pulomnary arteries to continue to the lung
blood flow returning from lungs
blood returning from the lungs flows through the pulomnary veins into the left atrium, then through the mitral valve into the left ventricle, and finally out through the aortic semilumar valve into the systemic circulation
atrioventricular valves
located between the atria and ventricles on both sides of the heart
prevent backflow of blood into the atria
tricuspid valve
valve on right side of heart, has 3 cusps
mitral valve
valve on left side of heart, has 2 cusps
semilunar valves
have 3 cusps and are located between the left ventricle and the aorta, and betwen the right ventricle and the pulmonary arter
sound of heartbeat
made by successive closing of the atrioventricular and semilunar valves
heart’s pumping cycle
made of 2 alternating phases- systole, and diastole, which make up the heartbeat together
systole
period during whci the ventricles contract forcing blood out of the heart into the pulmonary and systemic circulation
diastole
period of cardiac muscle relaxation during which blood drains into all 4 chabers
reflected in measurements such as blood pressure
systolic blood pressure
measures the pressure in a patient’s blood vessels when the ventricles are contracting
diastolic blood pressure
measures the pressure during caridac relaxation
cardiac output
defined as the total volume of blood the left ventrcle pumps out per minute
cardiac output= heart rate (number beats per minute) x stroke volume (volume of blood pumped out of the left ventricle per contraction)
control of heart rate
cardiac muscle contracts rhythmically without stimulation from the nervous system, producing impulses that spread through its internal conducting system
SA is the pacemaker
an ordinary cardiac contraction originates in and is regulated by the SA node
a small mass of specialized tissue located in the wall of the right atrium
spreads impulses through both atria, stimulating them to contract simultaneously
the impulse arrives at the atrioventricular node (AV) which conducts impulses to the rest of the heart, allowing enough time for atrial contraction and for the ventricles to fill with blood
the impulse is then carried by the bundle of His (AV bundle) which branches into the right and left bundle branches, and finally through the Purkinje fibers in the alls of both ventricles, stimulating a strong contraction
this contraction forces blood out of the heart and into circulation
how does the autonomic nervous system affect heart contraction
modifies it
the parasympathetic nervous system innervates the heart via the vegus nerve and causes a decrease in heart rate
the sympathetic nervous system innervates th heart via the cervical and upper thoracic ganglia anf causes an increase in heart rate
the adrenal medulla exerts hormonal contraol via epinephrine (adrenaline) secretion which causes an increase in heart rate
3 types of blood vessels
arteries
veins
capillaries
arteries
thick-walled, muscular, elastic vessels that transport oxygenated blood away from the heart
except for pulmonary artery which transports deoxygenated blood from heart to lungs
veins
thin-walled
inelastic vessels that conduct deoxygenated blood toward the heart
except for pulmonary vein which carry oxygenated blood from lungs to heart
much of blood flow in veins depends on their compression by skeletal muscles during movement rather than on the pumping of heart
venous circulation is often at odds with gravity, so larger beins, esp those in the legs have have valves that prevent backflow
capillaries
very thin walls made of a single layer of enothelial cells across which resp gases, nutrients, enzymes, hormones, wastes can diffuse
they have the smallest diameter of all 3 types of vessels; red bloods must often travel through them single file
lymph vessels
is a secondary circulatory system distinct rom the cardiovascular circulation
its vessels transports excess interstitial fluid called lymp to the cardiovascular system, thereby keeping fluid levels in the body constant
the smallest lymph vessels (lacteals) collect fats in the form of chylomicrons, from the villi in the small intestines and deliver them to the bloodstream
lymph nodes are swellings along lymph vessels containing phagocytic cells (lymphocytes) that filter the lymph, removing and destroying foreign particles and pathogens
lacteals
smallest lymphatic vessles
collct fats in the form of chylomicrons from villi in the small intestien and deliver them into the bloodstream, bypassing the liver
blood- components
human body has 4-6 litrs ofut
blood has both liquid compoenets (55%) and cellular (45%) components
plasma is liquid component- it is an aqueous mixture of salts, nutrients, resp gases, wastes, hormones, blood proteins
cellular components of blood are erythrocytes, leukocytes, platelets
leukocytes
WBCs
larger than erythrocytes and serve protective functions
platelets
cells fragments that lack nuclei and are involved in clot formation
many drugs inhibit platelet formation or adhesion to decrease clot development
erythrocytes, hemoglobin
RBCs
the oxygen carrying components of blood
contain about 250 million molecules of hemoglobin, each of which can bind up to 4 molecules of oxygen
when hemoglobin binds to oxygen it is called oxyhemoglobin
this is the primary form of oxygen transport in the blood
erythrocytes have a distinct bioncave, disk-like shape that gives them both increased surface area for gas exchange and greater flexibility of moevemtn through tiny capillaries
erythrocyte formation
are formed from stem cells in the bone marrow
their formation is stimulated by erythropoietin, a hormone made in the kidneys
in the bone marrow, erythrocytes lose thei nuclei, mitochondria and membraneous organelles
once mature they circulate in blood for about 120 days after which they are phagocytizd by special cells in the spleen and liver
finding immature erythrocytes in bloodstream is a sign of disease such as hemolytic anemia which is caused by rapid destruction of red blood cells due to an infection or disorder
A blood type
has A antigens, antibodies for B (anti-B),
can donate to A and AB
can recieve from A and O
B blood type
has B antigens
antibodies for A
can donate to B and AB
can recieve from B and O
AB blood type
antigens for A and B
no antibodies
can donate to AB only
can recieve from all (universal acceptor)
O blood type
no antigens
anti-A and anti-B
can donate to all- universal donor
can recieve from O only
Rh factor + drug for treatment
another antigen that may be present on cell surface of RBCs
individuals can be Rh- lacking the Rh antigen, or Rh+ possesing the Rh antigen
important during pregnancy
an Rh- can be sensitized to an Rh+ fetus if fetal red blood cells (which have the Rh factor) enter the maternal circulation during birth
if this woman then carries antoher Rh+ fetus, the anti-Rh antibodies she produced when sensitizedby the first birth may cross the placenta and destroy fetal red blood cells
can result in a tpe of sever anemia in fetus called erythroblastosis fetalis- is not caused by ABO blood-type mismatches between mother and fetus because anti-A and anti-B antobodies can’t cross thr placenta
Rhogam is drug made of a mixture of antibodies given to mothers who are Rh- to prevent their immune system from attacking the fetal red blood cells
Rh factor is also an issue with blood transfusions
patients who don’t have the Rh antigen can’t be given Rh+ blood, because their bodies will mount an immune response and reject the transfusion
carbaminohemoglobin
hemoglobin can also bind CO2
absorption of AA’s and simple sugars
are absorbed at intestinal capillaries
throughout body, metabollic waste products (watr, urea etc) diffuse into capillaries from surrounding cells which are then delivered to appropriate excretory organs
clotting cascade
platelets come into contact with exposed collagen of damaged vessel-> release a chemical that causes neighboring platelets to adhere to one another, forming platelet plug
then, both platelets and damaged tissue release clotting factor thromboplastin, which with the help of its cofactors calcium and vitaminK converts the inactive plasm protein prothrombin to its active form thrombin
thrombin converts fibrinogen (a plasma protein) to fibrin
threads of fibrin coat the damaged area and trap blood cells to form a clot
clot prevents extensive blood loss while damaged vessel heals itself
the fluid left after blood clotting is called serum
this complex series of reaction is called clotting cascade
platelet plug
platelets come into contact with exposed collagen of damaged vessel-> release a chemical that causes neighboring platelets to adhere to one another, forming platelet plug
thromboplastin
after platelet plug forms at damaged vessel site both platelets and damaged tissue release clotting factor thromboplastin, which with the help of its cofactors calcium and vitaminK converts the inactive plasm protein prothrombin to its active form thrombin
thrombin converts fibrinogen (a plasma protein) to fibrin
threads of fibrin coat the damaged area and trap blood cells to form a clot
thrombin
thrombin converts fibrinogen (a plasma protein) to fibrin
threads of fibrin coat the damaged area and trap blood cells to form a clot
inactive form is prothrombin
resp system airways
air passage consist of nose, pharynx (throat), larynx, trachea, bronchi, bronchioles, alveoli
gas exchange between the lungs and the circulatory system occurs across the very thin walls of alveoli which are air-filled sacs ar the terminals of he airway branches
resp system also provides a very large area for gas exchange, continually moving oxygenated air pver this area and protecting resp surface from infection, dehydration, temp changes
moves over vocal chords for sound prod and regulates body pH by regulating CO2 removal from blood
surfactant
protein complex excreted by cells in lungs
keeps lungs from collapsing by decreasing surface tension
premature babies dont always have this so must be given artificial superfactant until they can make their own
ventilation
regulated by neurons (referred to as respiratory centers) located in medulla oblongata
when the partial pressure of CO2 in the blood rises, the medulla oblongata stimulates increase in rate of ventillation
pulomonary capillaries
dense network of minute blood vessels surround the alveoli
gas exchange occurs via diffusion across these and the alveoili
oxygen diffuses from alveolar air into blood, while CO2 diffuses from blood into lungs
total lung capacity
the max volume of air the lungs can hold
tidal volume
the volume of air moved during a normal resting breath
significantly less than total lung capacit
inspiratory reserve volume
the volume of air that could be additionally inhaled into the lungs at the end of a normal resting inhalation
expiratory reserve volume
volume of air left in the lungs at the end of a normal resting exhalation
vital capacity
volume of air moved during a maximum inhalation followed by maximum exhalation
residual volume
even after maximum exhalation there is always air left in the lungs, called residual volume
