Circulatory System Flashcards
3 functions of the cardiovascular system
- maintain homeostasis
- regulation of body temperature
- transport of: metabolites+wastes, hormones, dissolved gases, cells for immune/inflammatory response
Components of the cardiovascular system (4)
- heart (pump)
- arteries + veins (vessels)
- capillaries (exchange sites)
- lymphatic vessels (drainage system)
2 circuits of circulatory system
- pulmonary circuit (to lungs)
- systematic circuit (to body)
Describe the role of pulmonary arteries/veins. How do these differ from systematic A/V?
PULMONARY: - arteries carry -O2 blood to lungs - veins carry +O2 towards heart from lungs SYSTEMATIC: - arteries carry +O2 away from heart - veins carry -O2 towards heart
What is a mediastinum?
- pleural cavity between the lungs, where heart is found
- also contains esophagus, trachea, thymus gland, blood vessels
The fibrous sac that surrounds the heart. Composed of a serous inner lining.
Pericardium
What is the direction of the wave of contraction in the heart?
- apex (inferior border) up to base (superior border) of heart
3 tissue layers of the pericardium
- visceral (epicardium- attached to heart)
- parietal
- fibrous (most outer)
The space between the visceral and parietal pericardium is called the _______ _______.
pericardial cavity (filled with pericardial fluid to reduce friction)
The wall of the heart is composed of 2 types of cardiac muscles:
- myocardium
- endocardium (inside of heart, very thin membrane)
Pulmonary artery
- deoxygenated blood from heart to lungs (exit right ventricle)
Pulmonary veins
- oxygenated blood from lungs to heart (enter left atrium)
Deoxygenated blood from upper body to heart (into right atrium)
Superior vena cava
Deoxygenated blood from lower body to heart (into right atrium)
Inferior vena cava
Aorta
- oxygenated blood from left ventricle to body
Coronary sinus
collects deoxygenated blood from myocardium - deposits into right atrium
Relaxation phase of the two ventricles
diastole
Contraction phase of the two ventricles
systole
Heart valves ensure _________ flow of blood.
one-way
close to prevent backflow
Another name for the mitral valve (left atrium to left ventricle).
bicuspid valve
Chordae tendineae (function, position found)
Fibrous tissue connecting papillary muscles to valves in tricuspid/ mitral valves (prevent backflow of blood back into atria).
What system exists to prevent the backflow of blood from the arteries to ventricles during diastole?
semilunar valves (pulmonary and aortic)
The cusps of the aortic semilunar valve drains into the ________ artery, feeding the heart freshly oxygenated blood.
coronary
During ventricular diastole, which valves are open/ closed?
Diastole = relaxed
- AV valves open
- semilunar valves closed
During ventricular systole
Systole = contraction
- AV valves active (closed)
- semilunar valves open
Explain the action in the heart in coordination to “lub-dub”.
lub = ventricles contracting, AV valves coming together dub = ventricles relax
The great cardiac vein (lies within anterior interventricular sulcus) becomes the coronary ______, expanding as more blood vessels drain into it.
sinus
Conduction system (5 components)
1) sinoatrial node (“pacemaker)
2) AV node (slows down)
3) AV bundle of His
4) R/L bundle branches
5) Purkinje fibres
What is the normovolemic blood in an average male body? Female body?
- male: 5-6L
- female: 4-5L
(due to body size)
What is the average pH range and temperature of blood?
- 38˚C
- 7.35 - 7.45
(if out of range, some functions do not work)
Erythrocytes are also known as?
red blood cells
White blood cells are also known as?
leukocytes
Red blood cells make up ___% of cells in blood.
99%
What action are platelets responsible for?
Clotting reaction in blood
Name the 5 types of leukocytes.
- neutrophil (attacks bacteria)
- eosinophil (anti-inflammatory)
- basophil (inflammatory)
- monocyte (become macrophages: eats invading elements)
- lymphocytes (immune response)
What kind of leukocyte attacks and destroys bacteria?
Neutrophil
What does an eosinophil do?
anti-inflammatory and allergic response
What kind of leukocyte enables an inflammatory response?
basophil
What kind of leukocyte differentiates into macrophages (phagocytic) to digest invading elements in the body?
Monocytes
What does a lymphocyte do?
immune response
What is a RBC made of?
water (66%)
proteins (33%)
(no nucleus - main function=gas transport)
What characteristic of a RBC allows a greater surface area for diffusion?
biconcave disc-shaped cell
Why does a RBC eject its nucleus and golgi apparatus during development?
These consume the O2 that the RBC is meant to deliver to tissues. Ejected to maximize gas exchange.
Are platelets cells?
Pieces of cells - pinched off from megakaryocyte (stem cell) from bone marrow
In which direction do continuous capillaries direct blood flow?
away from the heart
In which direction do fenestrated capillaries direct blood flow?
towards the heart
List the 3 layers of a blood vessel wall
- tunic interna (‘inner tunic’ lining)
- tunic media (elasticity)
- tunic externa (anchors)
Are arteries or veins harder to damage?
arteries
In an artery, which membrane layers are thicker than in veins?
Tunica media, externa
has more elastic fibres
Band of smooth muscle that adjusts blood flow through capillaries.
precapillary sphincter
What is the function of metarterioles?
shunt blood through capillary bed
From which structure do venules collect blood?
fenestrated capillaries
What structure exists within the walls of veins to prevent the backflow of blood?
valves
Define anastomosis.
Joining of arteries so it becomes continuous.
2 major differences b/n distribution of arterial + venous systems (in neck, limbs).
1) venous system more variable: # and location of veins (lower pressure, variations = less functional difference) // arterioles direct, grow towards active tissue
2) arteries are deep, protected by bone and soft tissue while veins are superficial AND deep
Artery whose only job is to feed the brain.
Internal carotid artery
Artery which feeds the head, neck, and face.
External carotid artery
This structure measures the amount of pressure existing within the vasculature, feeding this back to other structures in the body that can alter blood pressure.
Carotid sinus
This structure reads the chemical composition of blood, allowing the body to alter chemical composition.
Carotid body
This artery supplies the thyroid, shoulder and neck.
Thyrocervical trunk
This artery branches off from the subclavian and feeds the upper spinal cord and brain.
Vertebral artery
What is the name of the aorta superior to the diaphragm?
Thoracic aorta
What is the name of the aorta inferior to the diaphragm?
Abdominal aorta (goes posterior of diaphragm, NOT thru it)
Artery that branches anteriorly of aorta; branches to liver.
Celiac trunk
Artery that branches anteriorly of aorta; feeds spleen.
Splenic artery
Artery that branches anteriorly of aorta; feeds stomach.
Gastric branches
Artery that rises about 1.5cm inferior to celiac trunk, feeds 2/3 of GI tract.
Superior mesenteric artery
Artery that supplies the rest of the GI tract, colon.
Inferior mesenteric artery
After the aorta branches into a R/L side to extend to the lower extremities; before it leaves the body cavity.
R/L common iliac artery
Branches from the common iliac artery; remains inside of the body cavity and feeds pelvic organs.
R/L internal iliac artery
Branches from the common iliac artery; leaves the body cavity, working down into lower extremities.
R/L external iliac artery
Continuation of the axillary artery into the arm, once passed the teres major muscle.
Brachial artery (supplies arm)
Extension of the external iliac artery into the upper leg, running to popliteal fossa.
Femoral artery
Takes blood from the femoral artery, branches out into the tibial and fibular arteries in the lower leg.
Popliteal artery
Branches from the femoral artery; supplies lateral regions of skin, deep muscles of the thigh.
Deep femoral artery
Found on the posterior, lateral side of the lower leg.
Fibular artery
Passes between the tibia and fibula, descends towards the foot, providing blood to skin and muscles of anterior portion of the leg.
Anterior tibial artery
A vein that drains the spinal cord and posterior side of the skull.
Vertebral vein
Drains the facial vein; head, face, neck towards the brachiocephalic vein.
Internal jugular vein
Drains blood from the temporal and maxillary veins towards the brachiocephalic vein.
External jugular vein
A medial continuation of the axillary vein, drains into the brachiocephalic vein.. When this vein and the internal jugular meet, it forms the right brachiocephalic vein.
Subclavian vein
The R/L portions of this vein merges to form the superior vena cava. It takes blood from the head, neck, upper extremities and internal thoracic veins.
R/L brachiocephalic veins
Receives blood from the head, neck, chest, shoulders, and upper limbs.
Superior vena cava
A vein only found on the right side of thoracic body; a chief collecting vessel of the thorax: intercostal veins, esophageal, etc – drains into superior vena cava.
Azygos vein
A vein only found on the left side of the body, where intercostals drain into. (70-80% of ppl do not have this vein)
Hemiazygos vein
This vein collects blood from organs that lie inferior of the diaphragm.
Inferior vena cava
These veins drains the intercostal space and muscles.
Intercostal veins
These veins collect blood from the liver and are part of the portal system.
Hepatic veins
These veins collect blood from the kidneys.
Renal veins
These veins collect blood from the ovaries/ testes. The right side drains into the inferior vena cava while the left side drains into the left renal vein.
Gonadal vein
The R/L portions of this vein connects to form the inferior vena cava.
R/L common iliac vein
This vein drains pelvic organs from its respective side (glutes, sacrum, pelvic muscles).
R/L internal iliac vein
This vein drains the lower limbs, pelvis, and lower abdomen.
External iliac vein
Where do lymphatic veins drain into?
Inferior vena cava
This system allows blood from the digestive tract to drain directly to the liver. Composed of veins and arteries.
Hepatic portal system
This vein receives blood from the brachial and basalic veins, draining into the subclavian vein.
Axillary vein
This vein runs deep and receives blood from the radial and ulnar veins, draining into the axillary vein.
Brachial vein
This vein runs along the superficial, lateral side of the arm.
Cephalic vein
This vein runs along the superficial, medial side of the arm, joining the brachial vein to form the axillary vein.
Basilic vein
2 types of body fluids (think: location).
- intracellular fluid (cytoplasm, nucleoplasm)
- extracellular fluid (blood plasma; interstitial - lymph)
Where does interstitial fluid come from? Where does it go?
- fluid, small solutes from capillaries to surrounding cells
- blood pressure forces water+solutes out of plasma (72% of blood volume DAILY) - continual movement in and out of bloodstream (is returned)
- called ‘lymph’ when enters lymphatic system
What are the 3 components of “lymph”?
- interstitial fluid
- lymphocytes (immune response)
- macrophages
What is the function of primary lymphoid structures?
- responsible for production and maturation of lymphocytes – > contain stem cells for B, T, NK cells
- bone marrow, thymus
What is the function of secondary (peripheral) lymphoid structures?
- activated lymphocytes divide to produce additional lymphocytes of same type
- located “at the front lines” where invading bacteria are first encountered
- lymph nodes, spleen, tonsils
The lymphatic system is an alternative route for the transport of:
- hormones
- nutrients
- waste products
Compared to blood vessels, lymph flows passively along a _______ _________ (passively draws interstitial fluid into interstitial space, then back into venous system).
pressure gradient
skeletal muscle contraction + inhalation help move lymph thru lymph vessels
T/F
Lymphatic vessels have a smaller diameter than blood capillaries.
False.
Lymphatic capillaries larger in diameter and sectional view.
T/F:
Lymphatic capillaries have thinner walls, thus greater permeability. This is due to larger gaps between the endothelial cells (overlap instead of tightly bound), allowing larger macromolecules to enter as well.
True.
What is the function of valves in the lymph system?
- prevent backflow of lymph (minimal pressure)
- gradual flow of moving fluid
T/F
Approx 3.6L (72% of blood volume) enters the interstitial fluid every day.
True.
Vascular pressure forces water+solutes across capillary membrane into interstitial space. That fluid is then returned to the vasculature by the lymph vessels.
T/F
Some lipids absorbed by digestive tract enter bloodstream via lymph rather than capillaries of the vasculature.
True.
Because these big fatty acid chains do not get processed in the liver via bloodstream, it goes straight to the heart, depositing = calcification = hardening of arteries = aneurisms
Which parts of the body does the right lymphatic duct collect lymph from?
Right side superior to diaphragm.
Where does the thoracic duct drain from?
Entire body inferior of diaphragm; left side superior of diaphragm
Where does the cysterna chyli receive lymph from?
Receives lymph from abdomen, pelvis, lower limbs
This structure is a source of T lymphocytes. It has two lobes and lies in superior mediastinum. It begins larger in early life and undergoes involution in later life.
Thymus gland
This structure is the largest lymphoid organ.
- filters blood, removing abnormalities by phagocytosis
- stores iron from metabolized RBCs
- initiates immune response by B + T cells in response to circulating antigens
Spleen
located along left side of stomach
B-Lymphocytes (10-15%)
- originate + mature in bone marrow
- reside in lymph nodes, spleen, lymphoid tissue
- produce antibodies targeted to specific antigens
T-Lymphocytes (80%)
- originate in bone marrow
- mature in thymus gland
- cytotoxic T-cells
- regulatory T-cells
- reside in spleen, bone marrow, other lymphoid organs
Cytotoxic T-cells
Directly destroys pathogens + abnormal cells–> recognizes foreign cells/ infected cells
(cell-mediated immunity)
Regulatory T-cells
- made up of helper T cells + suppressor T cells
- activate/ inhibit activity of B cells
NK cells
aka large granular lymphocytes
“natural killer”
- originate + mature in bone marrow
- circulate thru peripheral tissue: immunological surveillance cells “policemen”
- attack foreign cells/ normal cells infected w/ viruses
- prevent cancer cells from spreading
What is the ratio of afferent (inwards) vs efferent (outwards) vessels in a lymph node?
afferent: many (pictured- 4)
efferent: ONLY one
How do lymph nodes filter the lymph?
Resident T+B cells + macrophages in sinus destroy 99% antiggens
Where within the lymph node do the B and T cells reside?
Lymph nodule
Where are the largest lymph “glands” (nodes) found [3]?
- base of neck
- axillae
- groin
(where peripheral lymphatics connect w/ lymphatic trunk)
What do “swollen glands” indicate?
Enlarged nodes due to inflammation or infection
What is a lymphoid tissue? What are the 2 types of this?
- connective tissues dominated by lymphocytes
- diffuse lymphoid tissue
- lymphoid nodules
Where does diffuse lymphoid tissue exist?
- mucous membranes of respiratory + urinary tracts
Where do lymph nodules exist?
(boundaries indistinct)
- mucosa of digestive tract:
- tonsils (pharynx)
- SI lining (Peyer’s patches)
- appendix (mass)
T/F
Lymphocytes are always effective against infection.
False.
Not always able to destroy bacterial/ viral invaders that have crossed epithelium –> infection develops–> tonsillitis, appendicitis
Why is an enlarged axillary lymph node a sign of breast cancer?
Cancer cells in breast metastasize (migrate) along lymphatics, becoming trapped in lymph nodes. 75% drainage of breast goes to axillary nodes. 20% goes to the other breast.
