heart Flashcards
DIFFERENCES IN FISH AND MAMMAL HEARTS
fish - single loop circulatory system where blood passes through the heart once per circuit/two-chambered - blood is oxygenated through the gills before being pumped to the rest of the body
mammals - double-loop circulatory system where blood passes through the heart TWICE per circuit/four-chambered - separation of oxygenated and deoxygenated blood, leading to efficient transport of oxygen to tissues
Skeletal vs cardiac muscles (5 pts.)
cardiac muscles are myogenic
Arteries
moving blood AWAY from the heart
Aorta
Carries oxygenated blood to the body from the left ventricle
Very thick, elastic muscle wall; can withstand very high pressure
Pulmonary artery
Four branches carry deoxygenated blood from the right ventricle to the right and left lungs
Thick, elastic muscle wall to withstand and maintain high pressure (although not as much as is generated in the aorta)
Coronary arteries
Arteries visible on the external surface of the heart
Carry the freshest, oxygenated and nutrient rich blood from the aorta to the heart muscle itself
Veins
Moving blood TOWARDS the heart
Superior vena cava and Inferior vena cava
Superior vena cava
- Brings deoxygenated blood from the head and upper body to the right atrium
- Large diameter, thin muscle wall, little pressure.
Inferior vena cava
- Brings deoxygenated blood from the lower body to the right atrium
- Large diameter, thin muscle wall, little pressure
Pulmonary vein
Bring oxygenated blood from the right and left lungs to the left atrium
Thin-walled, low pressure.
Cardiac veins
Veins visible on the external surface of the heart
Carry deoxygenated blood from the capillaries in the heart back to the right atrium
Remove wastes from the heart muscle
Pocket Valves
found in the blood vessels
leaving the heart:
- aortic & pulmonary semilunar valve (both have 3 semilunar cusps)
OTHER 2 TYPES OF valves:
tricuspid valve (blocks backflow from the right ventricle into the right atrium) & bicuspid valve (prevents backflow from the left ventricle into the left atrium)
WHY DO WE HAVE VALVES?
Valves prevent backflow of blood and keep the blood moving in one direction through the heart.
The transport system
nutrients, oxygen, heat, and hormones through a network of arteries, veins, and capillaries.
Components of Blood
Plasma - dissolves or carries all other components of blood, nutrients, wastes, etc.
Erythrocytes - transport oxygen
Leucocytes: phagocytes - eat up pathogens and dead cells / lymphocytes - for the immune response (create antibodies)
Platelets - clotting of blood following damage to cells
BLOOD VESSELS
Arteries carry high pressure blood away from the heart to tissues that need it (> than 10μm)
Capillaries are very small (around 10 μm diameter) and therefore can penetrate virtually every tissue in the body. Blood moves slowly through them under low pressure providing opportunities for the exchange of substances.
Veins carry the low pressure blood back to the heart using valves to ensure blood flows in the correct direction(variable but much larger than 10μm)
n.b. arteries and veins tend to be large structures, smaller arteries are known as arterioles and correspondingly smaller veins are venules.
STRUCTURE OF ARTERIES
- THICK MUSCULAR WALL AND FIBROUS OUTERLAYER HELPS WITHSTAND HIGH BLOOD PRESSURE
- SMALL LUMEN MAINTAINS HIGH BLOOD PRESSURE (LUMEN DECREASES WHEN MUSCLE CONTRACTS; INCREASES WHEN ELASTIC FIBRES STRETCH WITH EACH PULSE OF BLOOD)
STRUCTURE OF CAPILLARIES
- ALLOWS FOR EXCHANGE OF SUBSTANCES TO AND FROM THE BLOOD
- ALLOWS FOR TISSUES TO GAIN NUTRIENTS AND GET RID OF WASTE
- ALLOWS SUBSTANCES TO LEAVE ORGANISM; E.G., GASS EXCHANGE IN THE LUNGS W/ OXYGEN AND CO2
- wall is one cell thick, allows for easy diffusion because of short diffusion distance
- basement membrane is permeable
- wall & basement membrane can also have pores to quicken the rate of diffusion
- very small lumen, big SA, allows for the exchange of a lot of substances!
veins
Veins return blood to the heart for re-circulation. The flow is irregular.
The large lumen (compared to arteries and the thickness of the wall) means that the blood is under low pressure.
Because there is less pressure to resist the walls of the veins are thinner and less elastic than arteries. They also contain less muscle than the arteries.
Veins typically pass between skeletal muscle groups, which facilitate venous blood flow via periodic skeletal contractions.
Veins typically run parallel to arteries, and a similar effect can be caused by the rhythmic arterial bulge created by a pulse.
HAS VALVES
KNOW T- CHART
