The circulatory system in animals - 3.4 Flashcards
3.4
What is the Circulatory System and how does it function?
The circulatory system carries blood and dissolved substances such as oxygen and carbon dioxide to and from different parts of the body. The heart pumps blood and substances through the body via blood vessels.
What is the Closed Circulatory System and how does it function?
The closed circulatory system keeps blood within blood vessels, with the heart pumping blood through arteries, veins, and capillaries for efficient transport of oxygen, nutrients, and waste. Gas and nutrient exchange occurs in the capillaries.
What is blood and what does it consist of?
Blood is a tissue that consists of a liquid called plasma and cells.
Plasma (55%) - The liquid portion, containing water, proteins, hormones, and waste products.
Red Blood Cells (45%) - Cells that carry oxygen and carbon dioxide.
White Blood Cells (less than 1%) - Cells involved in immune response.
Platelets (less than 1%) - Small cell fragments involved in blood clotting.
What are red blood cells, their structure, function, and color?
Red blood cells (RBCs) are biconcave in shape, which increases their surface area for gas exchange and has no nucleus, allowing more space for hemoglobin. They contain hemoglobin, a protein that binds to oxygen and carbon dioxide, allowing for the transportation of oxygen and carbon dioxide. They appear red due to hemoglobin and dull dark red when deoxygenated.
What are white blood cells, their structure, function, and color?
White blood cells (WBCs) have a nucleus and varying shapes. They protect the body from infections by attacking harmful invaders and are white due to the lack of hemoglobin. WBCs are part of the immune system and are fewer in number compared to red blood cells.
What are platelets, their structure, function, and color?
Platelets are small, irregularly shaped cell fragments with no nucleus and they aid in blood clotting by forming a plug to stop bleeding and are colourless.
What is plasma, its composition, and function?
Plasma is the liquid component of blood, consisting mainly of water, proteins, hormones, nutrients, and waste products. It makes up about 55% of blood and is required to transportred blood cells, white blood cells, platelets, and other substances throughout the body. Plasma is pale yellow in color.
What is the double circulatory system?
The double circulatory system has two loops Pulmonary circulation carries deoxygenated blood to the lungs and the systemic circulation delivers oxygenated blood to the body.
What is the structure and function of arteries?
Arteries have a tough outer layer, a thick elastic middle layer, and a narrow lumen to withstand high pressure, transport blood away from the heart, and maintain high blood pressure. Arterioles are smaller branches of arteries that regulate blood flow into capillaries and control blood pressure.
What are the types of Arteries?
- Aorta – Largest blood vessel in the heart
- Pulmonary Artery – Carries blood containing carbon dioxide from your heart to your lungs
What is the structure and function of veins?
Veins have a tough outer layer, a wide lumen, and valves to prevent backflow. They return deoxygenated blood to the heart at low pressure and rely on skeletal muscle contractions to assist blood flow.
What are the types of Veins?
- Inferior Vena Cava – Where the blood enters the heart from the body.
- Superior Vena Cava – Where the blood enters the heart from the body.
- Pulmonary Vein – Carries blood-containing oxygen from your lungs to your heart.
What are venules and what is their function in the circulatory system?
Venules are small blood vessels that connect capillaries to veins. They collect deoxygenated blood from capillaries and transport it toward larger veins for return to the heart.
What is the structure and function of capillaries?
Capillaries have walls that are one cell thick and a very narrow lumen to reduce the distance for material exchange. Capillaries are the only blood vessels that exchange materials with the environment, allowing efficient gas and nutrient transfer between blood and tissues. Capillaries connect arteries with veins.
What is the Open Circulatory System and how does it function?
In an open circulatory system, blood flows freely in body cavities instead of being enclosed in vessels. The heart pumps blood into open spaces, where it directly bathes organs before returning to the heart. This system is found in insects and mollusks.
What are the difference between open and closed circulatory systems?
In an open circulatory system, blood flows freely in body cavities and directly bathes organs (e.g., insects). In a closed circulatory system, blood is contained in vessels, allowing more efficient transport of oxygen and nutrients (e.g., humans and fish).
What is the main function of the heart?
The heart pumps blood throughout the body, delivering oxygen and nutrients while removing carbon dioxide and waste through the circulatory system.
What are the four chambers of the heart?
The heart has two atria (left and right) that receive blood and two ventricles (left and right) that pump blood out. The left ventricle pumps oxygenated blood to the body, and the right ventricle pumps deoxygenated blood to the lungs.
How does blood flow through the heart?
Deoxygenated blood enters the right atrium, moves to the right ventricle, and is pumped to the lungs. Oxygenated blood returns to the left atrium, moves to the left ventricle, and is pumped to the body.
What is the difference between the pulmonary vein and the pulmonary artery?
The pulmonary vein carries oxygenated blood from the lungs to the heart, while the pulmonary artery carries deoxygenated blood from the heart to the lungs.
What is the function of heart valves?
Heart valves prevent the backflow of blood and ensure one-way flow. The tricuspid and bicuspid valves control flow between atria and ventricles, while the pulmonary and aortic valves control flow out of the heart.
What is the average resting heart rate?
70 bpm.
What is the cardiac cycle?
The cardiac cycle refers to the sequence of events that occur during one heartbeat, including the contraction and relaxation of the heart chambers to pump blood throughout the body.
How is tissue fluid formed and how does it circulate?
Blood from the aorta flows through arteries and arterioles into capillaries, where high pressure forces plasma through the capillary walls, creating tissue fluid. This fluid surrounds cells for nutrient exchange, and the blood then returns to the heart through venules and veins.
