Unit 5 Flashcards
What are the 5 functions of the circulatory system?
- Carries nutrients
- Carries hormones
- Distributes heat
- Regulates body fluid levels
- Provides immunity (defense)
What is the direction of blood flow in the circulatory system?
Heart → artery → arteriole → capillary → venule → vein
What is the function of arteries?
Arteries carry blood away from the heart and have thick, muscular walls.
What are arterioles?
Small arteries that can change diameter through vasoconstriction and vasodilation.
What is vasoconstriction?
The decrease in vessel diameter, making them narrower.
What is vasodilation?
The increase in vessel diameter, making them wider.
What is the role of the precapillary sphincter?
Regulates blood flow from arterioles into capillaries.
What are capillaries?
The smallest blood vessels, one cell thick, where diffusion occurs.
What are venules?
Small veins that carry blood from capillaries to veins.
What is the function of veins?
Veins carry blood back to the heart and have thin, smooth muscular walls with one-way valves.
What is the septum?
The muscle that separates the two sides of the heart.
What is cardiac muscle?
The muscle found in the heart, also called myogenic muscle.
What does pulmonary refer to?
Relating to the lungs.
What is the blood flow sequence through the heart?
Superior/inferior vena cava → Right atrium → Pulmonary veins → Left atrium → Tricuspid/AV valve → Semilunar valves → Right/left pulmonary artery → Lungs
What is the left ventricle’s role?
It is the most muscular heart chamber, responsible for pumping blood to the body.
What is the function of the AV valve?
Prevents the backflow of blood from the ventricles to the atria.
What is the function of the semilunar valve?
Prevents the backflow of blood from the arteries to the ventricles.
What is the coronary artery?
It supplies blood to the heart.
What is the cardiac cycle?
One heartbeat.
What occurs during systole?
The heart (ventricles) contracts, AV valves close, producing the ‘lubb’ sound.
What occurs during diastole?
The heart (ventricles) relaxes, semilunar valves close, producing the ‘dubb’ sound.
What is an electrocardiograph?
A record of the heartbeat.
What does systemic refer to?
Relating to the body.
What does portal refer to?
Relating to the liver.
What is normal blood pressure?
120/70 (systolic/diastolic)
What is a sphygmomanometer?
A blood pressure cuff.
Where is blood pressure greatest and lowest in the vessels?
Greatest in arteries and lowest in veins near the heart.
Where is blood velocity highest and lowest in the vessels?
Highest in arteries and lowest in capillaries for diffusion.
Where is surface area greatest in the vessels?
Greatest in capillaries for diffusion.
What factors increase blood pressure?
Vasoconstriction, old age, lack of exercise, and high salt intake.
What factors decrease blood pressure?
Vasodilation, exercise, and bleeding.
What is the SA Node?
The pacemaker of the heart.
What is the AV Node?
Sends electrical impulses to the ventricles.
What are Purkinje Fibres?
Fibres that carry nerve impulses through the septum to the ventricles.
What is an artificial pacemaker?
A device placed under the skin to control heartbeat when the SA node fails.
What external factors affect heart rate?
Sympathetic nervous system increases HR, parasympathetic nervous system decreases HR, exercise increases HR, and high temperature increases HR.
What is the role of the medulla oblongata?
It controls heart rate and breathing rate.
What is hypertension?
High blood pressure.
What is atherosclerosis?
The hardening of arteries due to fat build-up, which causes high blood pressure.
What is angina?
Chest pains due to poor circulation or less oxygen to the heart.
What is a heart attack?
A complete blockage of the coronary arteries, leading to heart muscle death due to lack of oxygen.
What is a stroke?
Lack of oxygen in the brain, with symptoms including trouble speaking or paralysis on one side.
What is an embolus?
A blood clot that dislodges and jams in another vessel.
What is an aneurysm?
A weak spot in an artery that can rupture.
What is the lymphatic system?
It returns extracellular fluid leaked from capillaries back to the circulatory system.
How is lymph moved?
By skeletal muscle and contains one-way valves.
What are lymph nodes?
They contain white blood cells (WBCs) that fight infection.
What are the components of blood?
Plasma (55%), White blood cells (WBCs) (<1%), Platelets (<1%), Red blood cells (RBCs) (44%)
What is plasma composed of?
92% water; proteins (fibrinogen), glucose, vitamins, minerals, gases, and waste.
What is an erythrocyte?
A red blood cell (RBC) with no nucleus that carries oxygen and contains hemoglobin.
What is a leucocyte?
A white blood cell (WBC) with a nucleus, the largest blood cell, responsible for immunity.
What is anemia?
A deficiency of red blood cells (RBCs) leading to low iron, low oxygen, and low energy.
What are platelets?
Small, fragile cells involved in blood clotting, made from stem cells in bone marrow.
What is blood clotting?
Fibrinogen (blood) + Thromboplastin (platelet) + Ca²⁺ (blood) = Fibrin (fibres)
What are the blood types?
A, B, AB, and O.
What are the characteristics of Type A blood?
Has A antigens, B antibodies; can receive from A and O; can donate to A and AB.
What are the characteristics of Type B blood?
Has B antigens, A antibodies; can receive from B and O; can donate to B and AB.
What are the characteristics of Type AB blood?
Has AB antigens, no antibodies; can receive from all; can donate to AB.
What are the characteristics of Type O blood?
Has no antigens, A and B antibodies; can receive from O; can donate to all.
What is the Rhesus factor?
An antigen on the RBC; if present, the person is Rh+ (A+, B+, AB+, or O+); if absent, Rh-.
What is erythroblastosis fetalis?
A condition in a second child (Rh+) where Rh antibodies from the mother can travel through the placenta and affect the baby’s blood.
What is sickle cell anemia?
A condition where hemoglobin is defective, changing the shape of RBCs and reducing oxygen transport.
What is hemophilia?
A condition where the blood cannot clot.
What is leukemia?
Cancer characterized by uncontrolled division of white blood cells (WBCs).
What are the immune system barrier responses?
Skin (dead cells, oil), Digestive System (acid & enzymes), Gas exchange (cilia, mucus, coughing, sneezing), Urinary system (mucus, urine).
What is the immune system non-barrier response (inflammatory)?
When a microbe enters the body: WBCs leave capillaries, WBCs engulf bacteria, lysosomes digest bacteria, pus forms.
What is the first step in the immune response?
An antigen enters the body.
What happens in the second step of the immune response?
A macrophage engulfs the antigen and pushes the antigen marker to the surface.
What happens in the third step of the immune response?
Helper T cells copy the antigen shape.
What happens in the fourth step of the immune response?
Helper T cells tell B cells to make antibodies.
What happens in the fifth step of the immune response?
Antibodies attach to antigens.
What are the sixth steps of the immune response?
6a: Macrophage engulfs antibodies; 6b: Killer T cells puncture antigens.
What are the seventh steps of the immune response?
7a: Suppressor T cells stop the response; 7b: Memory T cells remember the antigen.
How does HIV evade the immune system?
It does not leave glycoprotein on the surface of the cell and invades helper T cells.
What is an antigen?
A glycoprotein on the surface of a cell, acting as the cell’s signature.
What is an antibody?
A Y-shaped protein made by B cells in response to antigens, specific to the antigen.
What are vaccines?
They contain dead or weakened viruses.
What are antibiotics?
Substances made from bacteria or fungi used to treat bacterial infections.
What are the dangers of antibiotics?
1) Bacteria can become resistant; 2) Antibiotics cannot cure viruses; 3) Can cause side effects (allergic reactions).
What is deamination?
The removal of an amino group from protein, producing ammonia + CO₂ → urea.
What is the role of the kidney?
Site of blood filtration and urine production.
What is the renal artery?
It brings blood to the kidney from the aorta.
What is the renal vein?
It brings blood to the heart from the kidney.
What is the ureter?
It carries urine from the kidney.
What is the bladder?
The storage organ for urine.
What is the urethra?
It carries urine out of the body.
What is the renal cortex?
The outer layer of the kidney where filtration occurs.
What is the renal medulla?
The middle layer of the kidney, responsible for water reabsorption.
What is the renal pelvis?
It collects urine in the kidney and joins the kidney to the ureter.
What is a nephron?
The functional unit of the kidney that filters blood and makes urine, with approximately 1,250,000 per kidney.
What is the glomerulus?
A ball of capillaries involved in pressure filtration.
What is Bowman’s capsule?
It surrounds the glomerulus and is where urine enters the nephron (filtration).
What is the proximal tubule?
Connected to Bowman’s capsule, it is the site of reabsorption.
What is the loop of Henle?
It connects the proximal tubule and distal tubule and descends into the medulla.
What is the distal tubule?
It leads to the collecting duct and is the site of secretion.
What is the collecting duct?
It collects urine and carries it to the renal pelvis.
What is filtration?
The process from glomerulus to Bowman’s capsule, where cells, proteins, and lipids remain in the blood.
What is filtrate?
The fluid containing water, salt, glucose, amino acids, urea, and uric acid.
What is reabsorption?
The process from the proximal tubule to blood, returning substances like glucose, amino acids, minerals, salt, and water.
What is secretion?
The active transport of nitrogen wastes, H⁺ ions, and drugs from blood to the distal tubule, resulting in urine.
What is urine composed of?
Excess sugars, salts, H⁺ ions, water, urea, and uric acid.
What is ADH?
Antidiuretic hormone released when thirsty or dehydrated, increasing water absorption from the distal tubule and collecting duct.
What is aldosterone?
A hormone released due to low blood pressure, increasing sodium absorption from the loop of Henle, leading to less urine and increased blood pressure.
What is diabetes insipidus?
A condition where the body cannot produce ADH, leading to excessive urine production.
What are kidney stones?
Minerals forming solid crystals that can be removed by surgery, ultrasound, or catheter.
What is hemodialysis?
An artificial kidney machine used when the kidneys no longer work, filtering blood.
What is peritoneal dialysis?
A method using the membrane surrounding the abdominal cavity to filter blood, where dialysate fluid is pumped into the abdomen and later drained.
What is cardiac muscle?
Striated, tubular, and branched muscle found in the heart, with one nucleus per cell and involuntary contraction.
What is smooth muscle?
Non-striated muscle found in the digestive system, blood vessels, and eyes, with one nucleus per cell and involuntary, sustained contractions.
What is skeletal muscle?
Striated, tubular muscle attached to bones, with many nuclei per cell and voluntary contraction.
