Unit 4: Transport 1 Flashcards
Describe the heart.
Heart:
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle
Veins: Carry blood to the heart
- Superior/inferior vena cava
- Pulmonary veins
Arteries: Carry blood away from the heart
- Pulmonary artery
- Aorta
Valves: Prevent backflow of blood
- Atrioventricular valves
- Semilunar valves
Coronary artery:
- Branch of the aorta
- Brings oxygen to heart cells
Describe how blood flows through the heart.
- Blood enters the right atrium
a. comes from the body
b. through superior and inferior vena cava
c. this blood is deoxygenated - Both atria contract
a. pushes blood to the ventricles
b. through the open atrioventricular valves
c. blood goes from right atrium to right ventricle, and left atrium to left ventricle - Both ventricles contract
a. pushing blood through the open semilunar valves
b. pressure closes the atrioventricular valves to valves prevent backflow of blood - Blood from the right ventricle goes to the lungs via pulmonary artery
a. becomes oxygenated - Oxygenated blood from the lungs return to the left atrium via pulmonary vein
- Blood from left ventricle goes to body via aorta
a. left ventricle has the thickest muscle to push blood around body
How is a person’s heartbeat controlled?
The heart is a myogenic muscle: It contracts by itself.
- The pacemaker is located in the right atrium
a. also called the sinoatrial node (SAN)
b. pacemaker initiates heartbeat - SAN sends an electron signal that makes both a atria contract
- A little while later this triggers the atrioventricular node (AVN)
a. AVN Send an electric signal to the bottom of the ventricles
b. making the ventricles contract from the bottom up
i. this squeezes blood out of the heart
What other factors can affect a person’s heartbeat?
Two nerves from the medulla (part of the brain) can effect hearbeat
- accelerator nerve speeds up heart rate
- decelerator slows down heart rate
Adrenaline/ Epinephrine is a hormone that speeds up heartbeat
- released by the adrenal glands
What are arteries and what are their characteristics?
ARTERIES carry blood away from the heart
- blood is very high pressure
- arteries have a thick collagen layer
- an elastic layer to prevent arteries from bursting due to their high pressure - arteries have a narrow lumen (width of hole)
- maintains high pressure needed to push blood through body - arteries have thick muscle layer
- muscle squeeze between heartbeats to keep pressure high
What are veins and what are their characteristics?
VEINS carry blood back to heart
- blood is under low pressure
- veins have thin muscle and collagen
- low pressure so no risk of bursting - veins have wide lumen to help blood flow
- veins have valves to prevent backflow
What are capillaries and what are their characteristics?
CAPILLARIES connect arteries and veins
- bring oxygen and nutrients to your cells and take CO2 and waste away
- capillary lumen is one cell thick
- minimizes distance for diffusion - capillaries have many branches to increase SA for diffusion
- capillary wall/endothelium is only one cell thick
- minimizes distance for diffusion
What happens when there is an occlusion in the coronary artery, and what are the possible causes of occlusion?
Occlusion = Blockage/thrombose/clot
Coronary artery = The artery that provides nutrients and oxygen to the heart
- if this gets blocked heart does not get enough O2 and dies
- this causes a heart attack
- If blood vessels in the brain get blocked, it can cause a stroke
Occlusions build up because of high fat/sugar diets, diabetes, smoking and cholesterol
- Fat accumulates in the vessels and slowly blocks them
- Cholesterol can cause plaque/stiff artery walls that get damaged causing clots.
Causes of occlusion:
- high fat/sugar diet
- high cholesterol
- diabetes
- smoking
- plaques in blood vessels
What is blood composed of?
Blood is mostly made of water with polar substances dissolve in it
- gases (O2 and CO2), nutrients (glucose), Salts (NaCL) and waste (urea)
- water is called plasma
Blood has three main types of cells:
- Red blood cells = Erythrocyte
- carry gases (O2 in Hemoglobin) - White blood cells = Leucocytes
- fight disease - Platelets
- makes clots
What are the definitions of:
- Ventilation
- Gas exchange
- Respiration?
- Ventilation: Movement of air in & out of lungs
- Breathing - Gas Exchange: Diffusion of O2 from lungs to blood and CO2 from blood to lungs
- Diffusion of O2 from blood to cell, and CO2 from cell to blood - Respiration: Production of ATP using energy from food (NOT breathing )
- Aerobic respiration happens in the mitochondria of cells
Describe the structure of the lungs.
- Lungs
- Trachea
- Bronchus (2x)
- Bronchioles
- Alveolus
- Ribs
- Diaphragm
Describe the process of inhaling/inspiration.
Inhaling/inspiring is when air enters your lungs
During inspiration:
- External intercostal muscles contract, lifting the rib cage
- Diaphragm contracts and flattens
- This increases the volume of thorax/chest/torso
- This decreases the pressure in the thorax
- So, air enters lungs from higher air pressure outside
Describe the process of exhaling/expiration.
Exhaling/expiration is when air exits your lungs
During expiration:
- External intercostal muscles relax, dropping rib cage
- Diaphragm relaxes and curves upwards
- Internal intercostal muscles contract, pulling ribs down
- This decreasing the volume of the thorax
- This increases the pressure in the thorax
- So, air is pushed out of the lungs to lower air pressure outside
- Can force more exhalation by contracting abs
What are alveoli, and what is their function?
Alveoli are little bags in the lungs
Alveoli are the main surface of gas exchange
- O2 leaves alveoli and enters blood by diffusion
- CO2 enters alveoli and leaves blood by diffusion
How does the structure of alveoli facilitates gas exchange?
How the structure of alveoli facilitates gas exchange:
- Round shape and small size
a. Increases SA:V ratio for diffusion of gas - Many alveoli
a. High total SA for diffusion of gas - Alveoli are small
a. Maximizes SA: V ratio - Walls of alveoli and Capillaries are one-cell thick (very thin)
a. Small distance for diffusion of gas - Surrounded by capillaries
a. Small distance for diffusion of gas
b. Keeps difference in concentration of gases high, so diffusion is faster - Alveoli are moist
a. O2 and CO2 dissolve in water, making diffusion into blood easier
b. Surfactant reduces tension and prevents alveolar walls from sticking together
