bio 30 dec exam
superior vena cava
venous system, first one. recieves deoxygenated blood from the head and body
right atrium
venous system. second one. recieves deoxygenated blood via the superior and inferior vena cavae
right ventricle
venous system. third one. pumps deoxygenated blood to the lungs
inferior vena cava
venous system. fourth one. recieves deoxygenated blood from the lower body and organs
hepatic vein
venous system. fifth one. carries deoxygenated blood from the liver.
hepatic portal vein
venous system. sixth one. carries deoxygenated, nutrient rich blood from the gut for processing
renal vein
venous system. seventh one. carries deoxygenated blood from the kidneys.
pulmonary vein.
venous system. eighth one. carries oxygenated blood back to the heart, it is the exception
pulmonary artery
arterial system. first one. carries deoxygenated blood to the lungs. it is the exception
left atrium
arterial system. second one. recieves oxygenated blood from the lungs
left ventricle
arterial system. third one. pumps blood from the left atrium to the aorta
hepatic artery
arterial system. fourth one. carries oxgyenated blood to the liver
mesentertic artery.
arterial system. fifth one. carries oxygenated blood to the gut.
renal artery
arterial system. sixth one. carries oxygenated blood to the kidneys.
What are the main types of blood vessels in the circulatory system?
Arteries, arterioles, capillaries, venules, and veins.
What is the function of arteries?
To carry blood away from the heart under high pressure.
What is the function of veins?
To return blood to the heart under low pressure.
What prevents backflow in veins?
Valves.
What type of circulation occurs between the heart and lungs?
Pulmonary circulation.
What type of circulation occurs between the heart and the rest of the body?
Systemic circulation.
What is the purpose of coronary circulation?
To supply blood to the heart muscle itself.
What is the purpose of the hepatic portal circulation?
To carry blood from the digestive organs to the liver for processing.
What are the chambers of the heart called?
Atria (top) and ventricles (bottom).
How does the heart pump blood?
Top-Bottom-Out, at the same time.
What does the septum in the heart do?
It separates the left and right sides of the heart.
What are the main layers of an artery?
Endothelium- thin layer of epithelial cells, in contact with the blood
Tunica media- a central layer of elastic tissue and smooth muscle that can stretch and contract
Tunica externa- outer connective tissue layer with lots of elastic tissue, allows for expansion of the artery
Why is the left ventricle thicker than the right?
It pumps blood at higher pressure to the entire body.
What does the pericardium do?
It protects and anchors the heart and prevents overdistension.
What is the equation for cellular respiration?
C₆H₁₂O₆ + O₂ → CO₂ + H₂O + ATP.
How does blood flow from the body to the lungs?
Vena cavae → Right atrium → Right ventricle → Pulmonary artery → Lungs.
How does blood flow from the lungs to the body?
Pulmonary vein → Left atrium → Left ventricle → Aorta → Body.
What are capillaries?
Tiny blood vessels where gas and nutrient exchange occurs between blood and tissues.
What is blood pressure?
The force of blood against the walls of blood vessels.
Which blood vessel type has the highest blood pressure?
Arteries.
Which blood vessel type has the lowest blood pressure?
Veins.
What are the two main components of blood?
Plasma and formed elements (RBCs, WBCs, and platelets).
What is plasma made of?
Water, proteins, nutrients, hormones, and waste products.
What is the sinoatrial (SA) node?
The heart's natural pacemaker, because it produces the impulse that starts each heartbeat
What is the purpose of the atrioventricular (AV) node?
To delay the electrical impulse, allowing the ventricles to fill with blood before contracting.
What are the Purkinje fibers?
Specialized fibers that help distribute electrical impulses to the ventricles for contraction.
What is the largest artery in the body?
The aorta.
What is the largest vein in the body?
The vena cavae.
What is a heart murmur?
An abnormal sound caused by turbulent blood flow in the heart.
What is the function of the pulmonary valve?
To prevent backflow of blood into the right ventricle from the pulmonary artery.
What is the function of the aortic valve?
To prevent backflow of blood into the left ventricle from the aorta.
What is a pulse?
The rhythmic expansion and contraction of an artery as blood is pumped through it.
What is the average human resting heart rate?
Around 60–100 beats per minute.
What is hypertension?
High blood pressure.
What is an ECG (electrocardiogram)?
A test that records the electrical activity of the heart.
What is the cardiac cycle?
The sequence of events in one complete heartbeat, including systole (contraction) and diastole (relaxation).
What is cardiac output?
The volume of blood the heart pumps per minute.
What factors affect heart rate?
Exercise, stress, hormones, temperature, and medications.
What are baroreceptors?
Sensors in blood vessels that detect changes in blood pressure.
What is stroke volume?
The amount of blood ejected by the heart in one contraction.
Why do veins have thinner muscle layers compared to arteries?
Veins just flow blood back to the heart and don’t manage blood pressure or regional blood flow.
Why do veins have thinner elastic tissue compared to arteries?
Veins are under much less pressure, so they don’t need as much elastic tissue.
Why do veins have larger lumens?
Larger lumens allow veins to accommodate more blood flow at lower pressure.
Why do arterial walls need to be thick and elastic?
Arteries are close to the heart and must withstand high pressure from pumped blood.
Why do arterioles lack the elastic tissue found in larger arteries?
Arterioles are farther from the heart, where blood pressure is lower.
What is the purpose of smooth muscle in artery walls?
To maintain blood pressure and influence blood flow direction.
What happens to the diameter and blood pressure of an arteriole during vasodilation?
The diameter increases, and blood pressure decreases.
What does the QRS complex represent on an ECG graph?
The spread of the impulse through the ventricles, causing them to contract (ventricular systole). It appears as the rise and fall of the highest peak on the graph.
What does the P wave represent on an ECG graph?
The spread of the impulse from the pacemaker through the atria, causing atrial contraction (atrial systole). It occurs before the rise of the highest peak on the graph.
What does the T wave represent on an ECG graph?
The recovery of the electrical activity of the ventricles, which relax, signaling ventricular diastole and atrial diastole. It occurs after the fall of the highest peak on the graph.
Why is there a period of electrical recovery during each cardiac cycle?
It is due to ion pumping, which resets neurons for the next impulse.
Where does the greatest fall in blood pressure occur?
In the capillaries, despite their short distance in the circulatory system.
What makes the heartbeat sound?
Lubb- tricuspid and bicuspid valves close at the start of ventricular contraction (systole)
Dubb- semilunar valves close at the end of ventricular contraction
What factors affect blood pressure?
1. Cardiac Output – The volume of blood pumped by the heart per minute. This includes:
* Blood Volume: Less blood means lower pressure.
* Heart Rate: Faster heart rate increases pressure.
2. Arteriolar Resistance – The resistance to blood flow in the arterioles, influenced by:
* Size (Diameter): Smaller diameter increases resistance and raises blood pressure.
* Elasticity: Less elasticity (hardened arteries) increases resistance and raises blood pressure.
What is systolic pressure?
Systolic pressure is the pressure in the arteries when the ventricles contract and pump blood out of the heart. It's the higher value in a blood pressure reading.
What is diastolic pressure?
Diastolic pressure is the pressure in the arteries when the ventricles are relaxed between heartbeats. It's the lower value in a blood pressure reading.
How is blood pressure measured?
Blood pressure is measured using a sphygmomanometer. The cuff inflates to stop blood flow, and as the air is released, a stethoscope listens for sounds. The first sound heard is the systolic pressure, and when the sound stops, it’s the diastolic pressure. It’s recorded as systolic/diastolic in mmHg (e.g., 120/70).
How does the body regulate blood pressure?
Blood pressure is regulated by the autonomic nervous system (sympathetic and parasympathetic). When pressure is too high, the brain signals the heart to slow down and blood vessels to dilate. When pressure is too low, the heart rate increases, and blood vessels constrict to raise pressure.
What is the lymphatic system and its role?
The lymphatic system collects excess fluid (lymph) from tissues and returns it to the circulatory system. It has one-way valves, and its flow is assisted by muscle contractions. It helps protect against infection and plays a role in nutrient absorption.
What is the function of lymph nodes?
Lymph nodes filter lymph (previously interstitial fluid), trapping foreign substances like bacteria. They contain macrophages that destroy these substances through phagocytosis. Lymph nodes can swell when fighting infection.
What happens during shock?
In shock, blood pressure drops as blood pools in capillaries, reducing the amount of blood returning to the heart. The body compensates by constricting arterioles and prioritizing blood flow to the brain and heart. If untreated, shock can lead to organ failure.
What are the 3 other functions of the lymphatic system?
protection, circulatory, nutrient absorption (fats).
Vein Structure
Endothelium- thin inner layer of epithelial cells
Backflow valves- one-way valves located along the length of veins to prevent blood from flowing backwards
Tunica media- central thin layer of elastic and muscle tissue. smaller venules lack this layer
Tunica externa- thin layer of elastic connective tissues
Sympathetic Nervous System
involved in the fight or flight response
Parasympathetic nervous system
involved in relaxation
Parasympathetic vs Sympathetic
each of these subsystems operates in the reverse of the other (antagonism). Both systems affect the same organs and act in opposition to maintain homeostasis. For example: when you are scared, the sympathetic system causes your heart to beat faster; the parasympathetic system reverses this effect.
What does nitric oxide do?
Nitric oxide (NO) is also a potent dilator of blood vessels. When the endothelial cells that line blood vessels are stimulated, they synthesize nitric oxide. It quickly diffuses into the muscular walls of the vessels causing them to relax. This is why nitroglycerine is prescribed for angina