Chapter 34 Flashcards
What is a Circulatory System?
A system that moves substances into and out of cellular neighbourhoods.
What is Blood?
Blood is the transport medium in the circulatory system, typically it flows inside tubular vessels under pressure generated by a heart. Blood makes exchanges with interstitial fluid.
What is Interstitial Fluid?
Fluid in tissue spaces between cells.
What make up the body’s internal environment and what does it work to do?
Blood and interstitial fluid are the components that make up the body’s internal environment, and the body works to keep homeostasis.
What are the two main kinds of circulatory systems?
Open (most arthropods and mollusks) and closed (annelids and vertebrates).
What is an open circulatory system?
Blood moves through the heart and large vessels, but also mixes with interstitial fluid.
What is a closed circulatory system?
The blood remains inside a heart or blood vessel at all times, the total volume of blood moving continually away from the heart, through to vessels, and then back to the heart.
When does blood move fastest and when does it slow?
It moves fastest when confined to a few large vessels, and moves slowly when in blood capillaries; the vessels with the smallest diameter.
What did internally moistened sacs evolve into?
Lungs, which supported the move to dry land.
Explain the heart found in most fishes.
They have a one circuit, two chambered heart. The contractile force of this heart drives the blood through a capillaries bed inside each gill. From there the blood flows into a large vessel, then through capillary beds in body tissues and organs, and then back to the heart. Once the blood leaves the gill capillaries, it is no longer under much fluid pressure.
Explain the heart found in most amphibians.
The heart is divided into three chambers, with two atria emptying into one ventricle. Oxygenated blood flows from the lungs to the heart in one circuit, and a forceful contraction pumps it through the rest of the body in the second circuit. Oxygenated and oxygen-poor blood mix in the ventricle.
Explain the heart found in birds and mammals.
The heart has fully separate right and left halves, each with two chambers, and it pumps the blood in two separate circuits. With the two separate circuits, blood pressure can be regulated in each one. The strong contraction of the left ventricle pumps blood quickly through the systemic circuit, and the right ventricle can contract less strongly to protect the delicate lungs.
What is the pulmonary circuit? [Mammal heart]
Oxygen-poor, carbon dioxide rich, blood flows from the right half of the heart to the lungs. There it picks up oxygen, gives up carbon dioxide, and flows back into the left half of the heart.
What is the systemic circuit? [Mammal heart]
Longer than the pulmonary circuit, the heart’s left half pumps oxygenated blood to tissues where oxygen is used and carbon dioxide forms in aerobic respiration. Blood gives up oxygen and picks up carbon dioxide at tissues, then flows to the heart’s right half.
List the functions of blood.
- Fluid connective tissue.
- Carries oxygen, nutrients, and other solutes to cells and picks up their metabolic wastes and secretions (including hormones).
- Helps stabilize internal pH.
- Highway for cells and proteins that protect and repair tissues.
- [Birds and Mammals] Helps keep body temperature within tolerable limits by moving excess heat to skin.
What dictates blood volume and how much does the average human have?
Body size and concentration of water and solutes dictate the blood volume, the average-sized human has about 5 litres of blood (6-8% of total body weight).
What is Plasma?
The fluid portion of blood, it’s cellular portion consists of blood cells and platelets that arise from stem cells in bone marrow.
50-60% of the blood’s total volume is plasma, and the plasma is 90% water. It’s a transport medium for blood cells and platelets, as well as a solvent for hundreds of different plasma proteins and other molecules/ions.
What is a Stem Cell?
An unspecialized cell that retains a capacity for mitotic cell division. Some portion of its daughter cells divide and differentiate into specialized cell types.
What are Red Blood Cells?
Erythrocytes, or red blood cells, transport oxygen from lungs to aerobically respiring cells and carry carbon dioxide wastes from them. Mammals lose their red blood cell nucleus when they mature, becoming flexible disks with a depression in the centre. Oxygen binds to the hemoglobin, which when stored takes up 98% of the human red blood cell. It is what makes the blood appear red.
A mature red blood cell has enough sugars and other molecules to live about 120 days.
What is a Cell Count?
A measure of the quantity of cells of one type per cubic millimeter of blood.
What are White Blood Cells?
Leukocytes, white blood cells, function in daily housekeeping activities and in defense. Some are phagocytes that engulf damaged, dead, or dying cells, or “nonself” chemicals. Some types sound alarms when viruses, bacteria, or other pathogens attack the body. They can differ in size, nuclear shape, and staining traits. Their numbers fluctuate with levels of activity and state of health. B cells and T cells are specialized for immune response.
What are Platelets?
Megakaryocytes are ten to fifteen times bigger than other blood cells that form in bone marrow, and they break up into platelets which are membrane-wrapped fragments of cytoplasm. One formed, a platelet can last five to nine days. They release substances that initiate blood clotting when activated.
What are Red Blood Cell Disorders?
Two few red blood cells or deformed one result in anemias. Oxygen delivery slows and metabolism falters.
Polycythemia is a condition in which there are too many red blood cells. It makes blood more viscous and elevates blood pressure.
What are White Blood Cell Disorders?
Epstein-Barr virus causes infectious mononucleosis, in which too many monocytes and lymphocytes form. It causes fatigue, muscle aches, low-grade fever, and sore throats.
What is Agglutination?
A normal defense response where proteins called antibodies bind foreign cells and make them form clumps that attract phagocytes. It’s important for blood donors to be the same blood type of the recipient, so that the body doesn’t attack the donated blood.
What is ABO Blood Typing?
A method of analyzing variations in one type of self marker on red blood cells. There are two markers, and the presence of them determines if you have A, B, AB, or O (no markers present).
