What protects the heart?
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The rib cage.
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What protects the heart?
The rib cage.
What are the three main functions of the lymphatic system?
What is the function of pericardial fluid?
It reduces friction within the pericardium, allowing membranes to glide over each other during each heartbeat.
What is double circulation in humans?
A system where blood passes through the heart twice in one complete loop.
How does the composition of lymph compare to blood?
Lymph is similar to blood but lacks red blood cells, blood platelets, and plasma proteins.
What happens to absorbed lipids in the lymphatic system?
They are passed into the lymph and then into the blood.
What are the two upper chambers of the heart called?
Atria (singular: atrium).
What should be identified when examining blood smears?
Different blood cells.
What feature of veins helps reduce resistance to blood flow?
The large lumen of the veins.
What are some goals of scientists working on artificial hearts?
To produce artificial hearts using 3D printing technology and human body cells to reduce rejection problems during transplant.
What is the purpose of examining blood smears of people with blood diseases?
To compare the shape and number of different types of blood cells with those of healthy people.
What happens to the veins when skeletal muscles contract?
The veins are squeezed, forcing blood towards the heart.
What is the main function of the atria in the heart?
To receive blood at low pressure from the veins.
What is the average lifespan of red blood cells?
About 120 days.
What happens to blood flow in capillaries compared to arteries?
Blood flows slowly in capillaries, allowing more time for material exchange.
What happens to red blood cells in a 0.2% sodium chloride solution?
They will swell and may burst due to water entering the cells (hypotonic solution).
What are the names of the two types of valves that separate the atria from the ventricles?
Bicuspid valve and tricuspid valve.
What is lymph?
Fluid that enters lymph capillaries and has the same composition as tissue fluid.
What role do lymph nodes play in the lymphatic system?
They filter lymph and are part of the immune response.
What role do heart tendons play?
They prevent the bicuspid and tricuspid valves from turning inside out.
What is hydrostatic pressure in the context of tissue fluid formation?
It is the pressure of blood in the capillaries that is higher than the pressure of the surrounding fluid, forcing plasma components out.
What happens to blood pressure in arteries and arterioles?
Blood pressure is high due to the pumping action of the heart and changes periodically as the heart contracts and relaxes.
How do the walls of arteries compare to those of veins?
Arteries have thicker walls with more elastic tissue and muscles.
What do veins do?
Carry blood from the body tissues back to the heart.
How is lymph kept flowing in lymph vessels?
By the contraction of skeletal muscles next to the lymph vessels.
What causes the great drop in blood pressure in the capillaries?
The very narrow diameter of the capillaries.
What is the effect of capillaries having the greatest total cross-sectional area?
It allows for more time for the exchange of materials between blood and body cells.
Why do capillary beds provide a large surface area?
To allow for rapid exchange of materials between the blood and body cells.
What are the two blood vessels that supply blood to the liver?
Hepatic artery and hepatic portal vein.
Why is the larger lumen of vessel type II important?
It allows for increased blood flow and reduced resistance.
What is the function of the hepatic portal vein?
It links the small intestine to the liver, collecting nutrient-rich blood after digestion.
What role do antibodies play in the blood?
They are produced by certain white blood cells to help fight infections.
What does a blood smear of anaemia patients show?
A reduced number of red blood cells.
What allows arteries to distend and recoil?
The thick layer of elastic tissues.
How many flaps does the tricuspid valve have?
Three flaps.
Why is diffusion inefficient in large multicellular organisms?
Because cells in different parts of the body are far away from each other.
What is the purpose of a transport system in large multicellular organisms?
To ensure the supply of useful substances to target cells and removal of waste.
What is a key feature of cardiac muscles?
They can contract and relax continuously without fatigue.
How are materials exchanged between blood and body cells?
At the capillaries, useful materials diffuse out of the blood into the tissue fluid and then into the body cells, while waste products from body cells diffuse into the tissue fluid and then into the blood.
How is tissue fluid formed?
At the arteriole end of the capillary bed, higher blood pressure in the capillaries forces some plasma components (excluding plasma proteins) out to form tissue fluid.
What are the three types of blood vessels?
Arteries, veins, and capillaries.
What is the sequence of organs a red blood cell travels through after leaving the aorta?
Lungs, heart, small intestine, and liver.
Where does the red blood cell first return after flowing through the capillary?
Right atrium.
What advantage does double circulation provide for active animals?
It allows blood to be pumped at high pressure to meet the needs of respiration more efficiently.
What types of blood vessels do A and B belong to?
A is likely an artery and B is likely a capillary.
What do the coronary veins carry away from the heart?
Carbon dioxide and other waste.
What is the role of blood in the body?
It carries useful substances and waste to and from body cells.
What type of blood do arteries typically carry?
Oxygenated blood, except in the pulmonary artery and umbilical artery.
Where are red blood cells produced?
In the bone marrow of some bones like limb bones, ribs, and vertebrae.
What is anaemia?
A deficiency of either haemoglobin or red blood cells, leading to insufficient oxygen supply to body tissues.
What do venules do?
Join together to form veins.
Identify organ A based on the gas content of the blood.
Lungs.
What is the role of the vena cava?
To return blood to the heart.
What happens to lymph as it passes through lymph nodes?
White blood cells kill the germs in the lymph.
What assists the flow of blood in the aorta?
Recoil of the elastic wall of the aorta and the closing of the semi-lunar valves.
What type of blood does the left side of the heart receive?
Oxygenated blood.
What are the three main parts of the human circulatory system?
Blood, blood vessels, and heart.
What process occurred in the blood sample left at room temperature for one hour?
Clotting.
What role do white blood cells play in tissue fluid?
White blood cells can squeeze through the capillary walls and enter the tissue fluid.
How does oxygenated blood return to the heart?
It returns to the left atrium via the pulmonary veins.
Name three factors affecting the rate of enzymatic reactions.
Temperature, pH, substrate concentration.
What is the smallest type of blood vessel?
Capillaries.
How does a feature of vessel B facilitate the diffusion of oxygen from blood to body cells?
The thin walls of capillaries allow for efficient diffusion of oxygen.
What happens if the coronary arteries are blocked?
It can lead to reduced blood flow to the heart muscle, potentially causing chest pain or a heart attack.
What are three factors affecting the rate of diffusion of oxygen from blood to body cells?
Concentration gradient, temperature, and surface area.
How do capillaries connect arteries and veins?
They form a network that surrounds body tissues.
What occurs to the small amount of tissue fluid that does not return to the blood?
It drains into the lymph capillaries, which carry it back to the blood circulation.
How does nutrient-rich blood reach the liver after digestion?
Through the hepatic portal vein.
What is leukaemia?
A group of cancers that develops in the bone marrow, leading to the production of abnormal white blood cells.
What is the diameter of a capillary lumen compared to a red blood cell?
Slightly larger than the diameter of a red blood cell.
What is the role of arterioles in blood flow regulation?
The thick layer of muscles in arterioles contracts or relaxes to change the size of the lumen, regulating blood flow.
What is the difference in lumen size between arteries and veins?
Arteries have a smaller lumen compared to veins, which have a larger lumen.
What is the function of red blood cells?
Transport oxygen throughout the body.
What happens to tissue fluid when it enters lymph capillaries?
It is called lymph.
What is single circulation?
A system where blood passes through the heart only once, flowing in one complete loop, as seen in fish.
How does blood flow in relation to blood pressure?
Blood always flows from a region of high blood pressure to a region of low blood pressure.
What are the two major roles of plasma?
Transporting substances throughout the body and distributing heat to maintain body temperature.
What is the primary function of arteries?
To carry blood from the heart to the body tissues.
What provides the force for blood flow in veins?
The contraction of the skeletal muscles lying next to the veins.
What is the importance of tissue fluid for body cells?
Tissue fluid provides a relatively constant environment for normal functions of body cells and serves as a link for material exchange between blood and body cells.
What can red blood cells be given to treat?
Patients with anaemia or severe blood loss.
Which tissue type has the greatest number of mitochondria?
The inner wall of the small intestine.
What happens in the capillary beds?
Exchange of materials takes place between the blood and body cells.
What is the function of fibrinogen in the blood?
It is necessary for blood clotting.
What is plasma used for?
To treat patients with blood clotting problems.
What is the function of the atria in the heart?
To receive blood from the veins and pass it to the ventricles.
What are the main components of the human lymphatic system?
Lymph, lymph vessels, lymph nodes, spleen, thymus, and tonsils.
What does the pericardial fluid allow during heartbeats?
It allows the membranes to glide over each other.
How does the rate of flow of red blood cells through capillaries aid gas exchange?
It allows for more surface area contact with body cells, facilitating efficient oxygen and carbon dioxide exchange.
What is the direction of blood flow in arteries?
Away from the heart.
What is a key difference between blood and tissue fluid?
Blood contains red blood cells, while tissue fluid does not.
What is compared when examining blood cells?
Shape, relative size, and relative number of different types of blood cells.
What substances are transported by plasma?
Water, carbon dioxide, nutrients, urea, hormones, antibodies, and fibrinogen.
What do the coronary arteries supply to the cardiac muscles?
Oxygen and nutrients.
Why is there a significant drop in blood pressure along capillaries?
The small diameter of capillaries results in high resistance to blood flow.
Which factor contributes to the formation of tissue fluid?
Hydrostatic pressure in the capillaries is a key factor that contributes to the formation of tissue fluid.
What happens at the venule end of the capillaries regarding tissue fluid?
Water in the tissue fluid is drawn into the capillaries by osmosis due to lower water potential.
What do blood vessels do?
They form a system of tubes that distribute blood throughout the body.
What accounts for the change in blood pressure (P) in the capillaries?
The small lumen of the capillaries.
What happens to the artery when the heart relaxes?
The artery recoils.
What accounts for the change in blood flow rate (Q) in the veins?
The action of the skeletal muscles lying next to the veins.
Where are tonsils located and what is their function?
Located at the upper throat regions, they guard against germs entering the mouth or nose.
Why is the blood pressure in vessel P higher than in vessel Q?
Vessel P is likely an artery, which has higher pressure compared to veins like vessel Q.
How does blockage of the coronary artery at point R affect heart function?
It can lead to reduced blood flow to the heart muscle, potentially causing chest pain or heart attack.
What are the two systems that make up the transport system in humans?
The circulatory system and the lymphatic system.
Where are lipids absorbed in the body?
In the small intestine, specifically into the lacteals in the villi.
What is blood pressure?
The force exerted on the wall of a blood vessel by blood flow.
What is the primary function of valves in veins?
To prevent the backflow of blood.
What is the purpose of artificial hearts?
To temporarily replace the function of diseased hearts until a donor can be found.
What occurs in the lungs during double circulation?
Gas exchange takes place, and blood becomes oxygenated.
What occurs to the rate of blood flow when arteries branch into arterioles?
The total cross-sectional area increases, causing the flow rate to drop.
What are the different models of artificial hearts designed for?
Some provide an extra ventricle, while others replace the entire heart for patients with their heart removed.
What is the composition of tissue fluid compared to blood?
Tissue fluid is similar to blood but lacks red blood cells, blood platelets, and plasma proteins.
What are the three types of blood cells?
Red blood cells, white blood cells, and blood platelets.
What is the permeability characteristic of capillary walls?
Capillary walls are differentially permeable.
What provides the force for blood flow in veins?
The contraction of skeletal muscles that squeeze the vein.
What is the primary function of white blood cells?
To protect the body against diseases by killing germs.
Which blood vessel has higher blood pressure, M or N?
Blood vessel N.
Why is there a difference in carbon dioxide content between the blood in vessel types I and II?
Vessel type I carries blood away from the organ (deoxygenated), while vessel type II carries blood towards the organ (oxygenated).
What type of cells make up the capillary wall?
One-cell thick endothelium.
Why is the left ventricle's wall thicker than the right ventricle's?
It needs to provide greater force to pump blood to the entire body, except the lungs.
What is the role of arterioles in relation to capillaries?
Arterioles regulate blood flow to certain organs.
Where are the semilunar valves located?
At the base of the aorta and the pulmonary artery.
What is the function of fibrinogen?
To convert into fibrin for blood clotting.
What adaptation do the ventricles have?
A thick muscular wall that provides a strong force of contraction to drive blood over a long distance.
What is the role of structures P and Q in the heart?
They maintain unidirectional blood flow.
How does deoxygenated blood flow from the right atrium?
It flows to the right ventricle and is then pumped to the lungs via the pulmonary artery.
Where are arteries typically located in the body?
Deep inside the body.
What is double circulation?
A system that separates pulmonary and systemic circulation, allowing for higher blood pressure to body cells.
How do the structural differences between arteries and veins relate to blood flow?
Arteries have thicker walls to withstand high pressure, while veins have valves to prevent backflow.
What is the lumen size comparison between arteries and veins?
Arteries have a smaller lumen, while veins have a larger lumen.
What is the role of the left ventricle in systemic circulation?
It pumps oxygenated blood to all parts of the body except the lungs through the aorta.
Name one other kind of protein present in the upper layer of the blood sample after centrifugation.
Albumin.
What is the largest artery in the human body?
The aorta.
What role does the spleen play in the body?
Filters damaged cells and germs in the blood.
How does the structure of a pig heart compare to a human heart?
The pig heart has a similar structure to the human heart.
Which blood vessel has a thicker wall, M or N?
Blood vessel M.
What is the function of the heart in the circulatory system?
It acts as a pump to drive blood throughout the body.
How does blood pressure in arteries compare to that in veins?
Blood pressure is higher in arteries and lower in veins.
What is the average lifespan of white blood cells?
For most, less than 3 days.
How do capillaries regulate blood flow to organs?
By changing the lumen size, although they themselves cannot constrict or dilate.
What happens to blood after it flows through the liver?
It flows through the hepatic vein and then to the posterior vena cava to the heart.
What is the shape of red blood cells?
Biconcave disc shape.
What are two healthy habits to reduce the risk of blockage in the coronary artery?
Regular exercise and a balanced diet low in saturated fats.
What is the role of semilunar valves?
They prevent backflow of blood into the ventricles when the ventricles relax.
How do very small organisms like Amoeba transport substances?
By diffusion or streaming of the cytoplasm.
Where is the heart located?
Within the thoracic cavity between the two lungs.
What is the membrane surrounding the heart called?
Pericardium.
How does the lymphatic system protect us against disease?
White blood cells in lymph nodes kill germs that enter the lymphatic system, filtering them out before lymph returns to the blood.
Why do patients with the genetic disease lack energy?
Because abnormal red blood cells may not transport oxygen efficiently.
What is the first step in examining blood smears?
Examine prepared slides of blood smears of healthy people with a microscope under high-power magnification.
Why is single circulation sufficient for less active animals?
Because they do not require high blood pressure for efficient oxygen and nutrient delivery.
What are lymph capillaries?
Blind-ended vessels that join to form lymph vessels.
What type of muscle makes up the heart?
Cardiac muscle.
Why do plasma proteins, red blood cells, and blood platelets remain in the blood?
They are too large to pass through the capillary walls.
What is the main excretory product found in plasma?
Urea.
What are the names of the valves located on the right side of the heart?
Tricuspid valve and semilunar valve.
What is the function of valves in lymph vessels?
To prevent the backflow of lymph.
How does the rate of blood flow change along the blood vessels?
It is high in the arteries, drops in the arterioles, nearly zero in the capillaries, and increases in the veins.
What is the role of arterial recoil?
It pushes blood forward after the artery distends.
What happens to most of the tissue fluid?
It returns to the blood at the venule end of the capillaries.
Why is the center of red blood cells lighter in color under a microscope?
Due to the absence of a nucleus in mature red blood cells.
What happens to waste products like carbon dioxide in the exchange process?
They diffuse from body cells into the tissue fluid and then across the capillary wall into the blood.
What are the four layers of tissues in arteries and veins?
Fibrous tissue, smooth muscles, elastic tissues, and endothelium.
What do the smallest blood vessels allow?
Exchange of materials between blood and body cells.
Why do arteries have thick walls?
To withstand high blood pressure due to the pumping action of the heart.
Where is the bicuspid valve located?
On the left side of the heart.
Which blood vessel carries blood with the highest urea content?
Renal vein.
What does the bicuspid valve prevent?
Backflow of blood from the left ventricle to the left atrium when the left ventricle contracts.
What are potential health issues caused by a large septal defect?
Increased workload on the heart and lungs, leading to high blood pressure and possible damage to lung blood vessels.
What is one visible difference between red and white blood cells?
Red blood cells are biconcave and lack a nucleus, while white blood cells have a nucleus and are larger.
What is the function of the bicuspid, tricuspid, and semilunar valves?
To prevent backflow of blood in the heart and ensure blood flow in one direction.
What is the main component of plasma?
Mostly water, making up 90% by volume.
What type of blood does the right side of the heart receive?
Deoxygenated blood.
What components of plasma are forced out of capillaries to form tissue fluid?
Water, minerals, sugars, lipids, and hormones.
What is the upper layer obtained after centrifugation of the blood sample called?
Plasma.
How does blood pressure change along the blood vessels?
Blood pressure is high in the arteries, gradually drops in the arterioles, experiences a great drop in the capillaries, and becomes even lower in the veins.
What is the volume percentage of plasma in blood?
55% by volume.
Do arteries have valves?
No, except at the base of the pulmonary artery and the aorta.
What is the role of heart tendons?
They support the heart valves.
What are two functions of the thick muscular wall of vessel type I?
Maintains blood pressure and regulates blood flow.
How does deoxygenated blood return to the right atrium?
It returns through the venae cavae.
What is the function of heart valves?
They ensure blood flows in one direction only in the heart.
How is blood flow increased in veins despite low blood pressure?
Due to the contraction of skeletal muscles lying next to the veins.
What is the thickness of a capillary wall?
One-cell thick.
What happens to red blood cells in a 2% sodium chloride solution?
They will shrink due to water leaving the cells (hypertonic solution).
What is the role of the umbilical artery and vein?
They connect the embryo to the placenta in mammals.
Why does blood flow rate increase in the veins?
Due to the contraction of skeletal muscles next to the veins.
How are the structures of arteries, veins, and capillaries related to their functions?
They have different structures that are closely related to their specific functions.
What is a septal defect?
A condition where the wall between the left and right chambers of the heart fails to close completely, leaving a hole.
What roles do white blood cells serve?
They protect against diseases, with some acting as phagocytes to kill and digest foreign cells.
Where does fluid in the circulatory system eventually return to the heart?
Left atrium.
What happens during pulmonary circulation?
Deoxygenated blood is pumped from the heart to the lungs for oxygenation.
What happens to the oxygen content of blood when it flows from X to Y?
It increases.
What are the two lower chambers of the heart called?
Ventricles.
What is blood composed of?
Blood cells suspended in plasma.
Where do lymph vessels connect?
To two large veins near the neck region.
What are the names of the valves located on the left side of the heart?
Bicuspid valve and semilunar valve.
What is the primary function of red blood cells?
To carry oxygen due to the presence of hemoglobin.
What is the primary function of capillaries in the circulatory system?
Exchange of materials between the blood and body cells.
Who receives blood platelets?
Patients who are unable to produce enough platelets.
What feature is common to an air sac and an intestinal villus for facilitating diffusion?
They have numerous capillaries.
What happens to blood pressure in veins and venules?
Blood pressure drops to nearly zero after traveling a long distance from the heart.
What is the role of the left atrium?
To receive oxygenated blood from the pulmonary veins.
What do the spleen and thymus produce?
White blood cells that kill germs and destroy dead cells.
How do the atria contribute to blood circulation?
They contract to pump blood into the ventricles.
What are the symptoms of anaemia?
Patients feel weak and may faint easily.
What distinguishes the ventricles from the atria?
Ventricles have a thicker muscular wall than the atria.
What may indicate a bacterial infection in relation to lymph nodes?
Swelling of the lymph nodes.
What happens to arteries when the heart contracts?
Blood is forced out, causing the arteries to distend.
What happens in the case of a ventricular septal defect?
Oxygenated blood from the left ventricle mixes with deoxygenated blood in the right ventricle.
What role do lymph nodes play in the lymphatic system?
They filter out germs from the lymph before it returns to the blood.
Which chamber of the heart has the highest blood pressure?
Left ventricle.
What is the correct change in glucose content when blood flows from X to Y?
Remains unchanged.
What is the function of the septum in the heart?
It prevents the mixing of oxygenated and deoxygenated blood.
What happens when blood is spun in a centrifuge?
It separates into two layers: plasma on top and blood cells at the bottom.
Which food item is most suitable for a person suffering from anaemia?
Spinach.
Where does the exchange of materials between blood and body cells occur?
At the capillary bed.
What occurs when the heart contracts?
Blood is forced into the artery, causing it to distend.
What type of blood does the right atrium receive?
Deoxygenated blood from the anterior and posterior vena cava.
How do small molecules like oxygen and nutrients move from capillaries to body cells?
They are forced out of the capillary wall into the tissue fluid and then diffuse into body cells.
What condition do white blood cells help treat?
Insufficient white blood cells and infections.
What is the overall benefit of donating blood?
Donating blood saves lives.
What is the function of the right ventricle?
To pump deoxygenated blood to the lungs via the pulmonary artery.
Which blood vessel carries blood with the highest oxygen content?
Hepatic artery.
What happens to hemoglobin when red blood cells are destroyed?
It is broken down into iron, which is reused, and bile pigment, which is excreted.
What is the role of the ventricles in the heart?
To pump blood away from the heart to the body.
What happens to the total cross-sectional area as blood moves from arteries to capillaries?
The total cross-sectional area increases, leading to a drop in flow rate.
What is the size of a typical lymphocyte?
Diameter about 6–10 μm.
What does a blood smear of leukaemia patients show?
An increased number of white blood cells.
Which blood vessels branch into capillaries at both ends?
Arteries and veins.
What is the role of eosinophils?
They are involved in allergic reactions.
What prevents the heart valves from turning inside out during ventricular contraction?
Tough heart tendons, also known as chordae tendineae.
What is the plural form of 'vena cava'?
Venae cavae.
What is the function of blood platelets?
Involved in blood clotting to prevent further blood loss and entry of germs.
How does the elasticity of artery walls contribute to blood flow?
It allows arteries to recoil, which helps maintain continuous blood flow.
Explain the low oxygen content of the blood in vessel type I.
It is returning from the tissues where oxygen has been used for metabolism.
Where are white blood cells produced?
In the bone marrow and spleen, maturing in lymph nodes.
What are the five types of white blood cells?
Neutrophil, eosinophil, basophil, monocyte, and lymphocyte.
What is the role of neutrophils?
They act as phagocytes to kill and digest foreign cells such as bacteria and viruses.
What characteristic of capillaries allows for rapid diffusion of materials?
The one-cell thick wall provides a short distance for diffusion.
