Circulatory System Quiz Flashcards
Do all organisms require a circulatory system?
No, single celled organisms, sponges and yeast are examples as they don’t need to transport oxygen or nutrients (they can just absorb them as they are directly exposed to environment)
What are the functions of a circulatory system? (6)
- Delivers O2 from respiratory system
- Delivers nutrients from digestive system
- Delivers hormones from endocrine system
- Delivers chemicals or cells from immune system
- Delivers metabolic wastes from cells to kidneys and liver
- In warm-blooded animals, it plays a role in distributing thermal energy throughout body to maintain body temp
What are the 3 main features of circulatory systems?
- A fluid that circulates materials through the body
- A network of tubes in which the fluid circulates
- A pump that pushes the fluid through the tubes
What are open circulatory systems? (5)
Found in most invertebrates (snails, insects, crustaceans)
Circulatory fluid (hemolymph - mixture of blood and tissue fluid) pumped into interconnected system of body cavities (sinuses) where it bathes the cells directly
Contractions of one or more hearts forces hemolymph out circulatory tubes through sinuses
When the heart relaxes, hemolymph is drawn back to heart through open ended pores (pump and bucket)
Body movement can help circulation
What is a closed circulatory system? (3)
All vertebrates and some invertebrates have them (earthworms, squid, octopus)
Fluid (often blood) is contained w/in a network of tubes or blood vessels which separates the blood and the tissue
Tissue fluid surrounds the cells and provides a medium for diffusion of substances from the bloodstream to the cells (open-blood and tissue mix in tissues)
What is a two-circuit circular system?
Mammals, birds and crocodilians have it
Circulation to the lungs is separate from circulation to the body
2 parts - pulmonary circuit: delivers blood to lungs; systemic circuit: delivers blood around the body
How many liters of blood die the human body contain?
4-5L
What is the circulatory system made of?
Cellular component and intercellular component (plasma)
What is plasma?
Protein-rich liquid in which blood and platelets are suspended
Made mostly of water but also contains albumins, globulins and fibrinogen
What are albumins?
Determine how much water enters or leaves bloodstream
What are globulins?
Transport lipids, cholesterol, some fat-soluble vitamins and some minerals (immunoglobulins/antibodies- fight infectious diseases)
What are fibrinogens?
Plays a critical role in blood clotting
What does the cellular component consist of?
Red blood cells, white blood cells and platelets
What are red blood cells? What is the main function? How do they form? Is there a nucleus? How many days does it spend in circulation?
Aka erythrocytes
Shaped in Biconcave disks
Main function: carry O2 from lungs to body and carry CO2 from body to lungs
Formed from stem cells in marrow of vertebrae, ribs, breastbone, skull and bones of arms and legs
Has a nucleus when developing but it dissolves after
Spend about 120 days in circulation
What are white blood cells? Where are they formed? What are the 2 categories?
Aka leukocytes
Formed in bone marrow as well
2 categories are granular and agranular
What are granular leukocytes? What are the three kinds?
Have granules in their cytoplasm
Neutrophils: play role in immune system; first to travel to infection site; ingest microorganisms
Eosinophils: play role in immune system; releases enzymes during infection, allergic reaction and asthma
Basophils: play role in immune system; releases enzymes during allergic reaction and asthma
What are agranular leukocytes?
Specialized for engulfing bacteria and other microorganisms
Use phagocytosis to destroy bacteria/harmful substances (engulfs it and then releases enzymes to break it and the WBC down - pieces left behind as pus)
Two kinds- lymphocytes and monocytes
What are lymphocytes?
Produce antibodies that attack microorganisms or their toxins
What are monocytes?
Enlarge to become macrophages
Clean up bacteria, dead cells and other debris in bloodstream and tissue
What are platelets?
Small cell fragments produced from stem cells in the bone marrow
Essential in blood clotting, or coagulation
What are the three types of blood vessels?
Arteries, veins and capillaries
What are arteries?
Blood vessels that carry blood away from the heart toward body tissues
What is the aorta?
The single large artery that leaves the heart
It branches into other major arteries that carry blood through the body
What happens when the heart pumps blood?
Arteries expand in diameter to accommodate the increased pressure
When the heart relaxes, they return to normal size pushing blood further down the vessel (like a water balloon)
Where can we feel the movement of blood?
Pulse points, like inner wrist, throat, inside of elbow, etc
What are arterioles?
The smallest arteries that have smooth muscles in its wall that allow it to be controlled by the nervous system
How does the nervous system control arterioles?
Nervous system will constrict or dilate arterioles in response to external stimuli - both a cooling and heat retention strategy
What is vasodilation?
When body is overheated, nerve impulses send a message to relax muscles in arterioles in the skin which causes them to increases in diameter
A cooling strategy as warm blood close to the surface of the skin will lose thermal energy to surrounding environment
Cooled blood will circulate to the rest of the body to cool it
What is vasoconstriction?
Nerve impulses cause smooth muscles in the arterioles to contract
Diameter of vessels narrow in response to cold temperatures which makes less blood flow near the surface of skin, reducing amount of heat lost to the environment
Construction directs blood flow to places it is most needed
What does construction do when resting?
Divert blood from muscles to organs like stomach and intestines as they are what needs it
What does construction do when resting?
Reduces blood flow to organs and diverts it to muscles which are more in use
What are capillaries?
The smallest vessels at the end of arterioles
Role is to supply oxygen and nutrients to the cells of the body
How extensive is the network of capillaries? How thick are the walls?
No body cells or father than two cells away from a capillary
1 cell thick to make diffusion in and out easier
How are capillaries controlled?
Don’t have smooth muscles so they can’t be controlled by nervous system
Instead pre-capillary sphincters serve the same function
What are venules? What are veins?
Venules are the smallest veins that are attached to opposite end of the capillaries
Venules merge to form veins
What do veins do?
Carry deoxygenated blood, carbon dioxide and waste away from tissues
Takes blood from capillaries back to heart
What are varicose veins?
Veins become less elastic and have damage to valves as people age
Damage to valves can cause bulges where the blood pools called varicose veins
What are the two numbers on blood pressure readings?
Systole/Systolic pressure: period in cardiac cycle where ventricles contract causing blood to be ejected from the ventricles; 1st number
Diastole/Diastolic pressure: when ventricles are relaxed (ventricles full with blood); 2nd number
What are the two major roles of the Lymphatic System?
Helps ensure blood volume is maintained in circulatory system
Filters bacteria and other components from blood in immune system
What is the purpose of the lymphatic system? What is it composed of? (4)
As blood circulates, some proteins leak out of the capillaries
Excess fluid is collected in lymph vessels and is returned to the blood in the veins
Composed of lymph vessels, lymph nodes, spleen and thymus
What are lymph nodes?
Nodes in the lymph vessels
Acts as a filter to remove bacteria and foreign particles
What is the spleen?
Large organ of lymphatic system
Acts as filter and reservoir of erythrocytes and leukocytes
What is a thymus?
Glandular organ
Secretes hormones to promote maturity of lymphocytes
What are the two circuits of the heart?
Pulmonary circuit- the part that delivers blood to the lungs
Systemic circuit- the part that delivers blood around the body
Where is the heart located? What is it’s structure? What is it mostly composed of?
In the middle of the chest under the breastbone between the lungs
Hear is enclosed in a sac (pericardium) which is a two layer wall. Between the walls is a lubricating fluid that allows the walls to slide over one another as the heart beats without friction from other organs
Heart is mostly composed of cardiac muscle (type that is exclusive to heart and has ability to contract and relax quickly)
How man chambers does the heart have?
4; left atrium, right atrium, left ventricle and right ventricle
Where are the atria? Which side does what? What does the cardiac muscle in the atria do?
At the top of the heart, 1st to receive blood from around body and from lungs
Right atrium receives blood from body
Left atrium receives blood from lungs
Lines the walls and is very thin because atria are responsible for pumping blood into ventricle (a short distance)
What are ventricles? How are the muscles arranged? What happens when they contract?
Bottom part of the heart with thick walls that are more powerful than atria. They pump blood throughout the body (left to body tissues, right to lungs; making left side stronger as it pumps to more places)
Muscles arranged in spiral around the heart; when they contract it produces a slight twisting motion that rings the blood out of the heart
What separates the left and right side of the heart? How do the sides pump in relation to each other? Which ways do blood flow?
The septum
Sides pump in sync, so they happen at the same time
Blood flows one way, always the same direction, with help from valves to stop blood from flowing backwards
What are the two types of valves?
Atrioventricular: separate atria and ventricles (bicuspid on left, tricuspid on right)
Semilunar: separate ventricles and arteries (pulmonary valve of right, aortic valve on left)
What is a cardiac cycle?
A single heart beat, where there is actually 2 contractions as one pump brings blood in right side and out and the other brings blood in left side and out
Makes a lub-dub sounds
What are the chordae tendinae?
Tendons in the ventricles that prevent AV valves from opening backwards (heartstrings)
What is the sinoatrial , or SA, node?
A specific region in the right atrium that sends an electrical signal to both atria, causing them both to contract. This causes blood to be pushed out of the atria and fill ventricles
What is the atrioventricular, or AV, mode? Where is the impulse sent?
A specific region in the right atrium that receives a signal from SA node when it sends its impulse, triggering the AV node to send out its electrical signal.
The impulse send to Purkinje fibers which are special conducting fibers that run down the septum
This causes both ventricles to simultaneously contract, sending blood to lungs and body tissues
What are the lub and dub sounds you hear when using a stethoscope?
The lub sound is made by the closing of the atrioventricular valves (ventricular systole)
The dub sounds is made by the closing of the semilunar valves (ventricular diastole)
How is the heart controlled?
The heart mainly controls itself but brain and hormones can influence the frequency
During times of increased body activity, heart rate increases to releases more O2 from body cells. The brain sends a signal to adjust the frequency.
Hormones like adrenaline can also affect frequency
How can you analyze a heartbeat?
Cardiac cycle can be monitored using electrocardiograph which measures electric signals and produces an electrocardiogram
Explain the flow of blood.
Deoxygenated blood from the body travels through the superior and inferior vena cava into the right atrium. Then blood flows through the atrioventricular valve, or the tricuspid valve, into the right ventricle. Blood then flows through the semilunar valve, or pulmonary valve, into the pulmonary artery and goes to the lungs (blood from left pulmonary artery goes to the left lung, blood from right pulmonary artery goes to the right lung; both pick up O2 and release CO2). The now oxygenated blood returns to the heart through the left and right pulmonary vein. The blood flows from the pulmonary veins into the left atrium then through the atrioventricular valve, or bicuspid valve, into the left ventricle. Blood then flows through the semilunar valve, or aortic valve, into the aorta. Finally blood flows from the aorta to all parts of the body before the cycle repeats.
