Circulatory system Flashcards
Circulatory system
→ Helps pump blood throughout the body.
→ Provides nutrients to cells
→ Helps remove waste from cells
→ Temperature regulation
Heart
Pumps blood throughout the body and back to the lungs.
The heart generates a high hydrostatic pressure to pump blood out of the heart, while also creating low pressure to bring it back in.
Made up of the Right Atrium, Left Atrium, Right Ventricle and Left Ventricle (Chambers that create the necessary pressure to pump blood).
Has pulmonary arteries which carry deoxygenated blood to the lungs where CO2 is exchanged for Oxygen.
Blood Vessels: Arteries
Carry oxygenated blood away from the heart (these usually have a thicker anatomy)
→ Carry blood at high pressure, thus thick and stretchy walls
Blood Vessels: Viens
Carries Deoxygenated towards the heart (thinner in anatomy)
→ These have one-way valves (venous valve) to ensure that the blood does not flow back due to gravity.
Blood vessels: Capillaries
Capillaries link the arteries and veins together at conjunctions.
→ Thin walls (Single layer epithelial tissue) and are narrow, where diffusions of oxygen, carbon dioxide and other wastes occur.
→ These capillaries are connected to venules and arterioles which are basically smaller arteries and veins.
→ If it is cold, sphincters will form and close off some capillaries, so that the blood is not exposed to the cold and less heat is lost. (thus numbness)
↑ If this gets to a certain point, your arteries and veins will constrict to lower blood flow and lose less heat.
↑ On the contrary, if you are working a certain body part, the vessels will expand to let blood flow.
Blood pressure
A measure of how much strain your arteries feel when blood is pumped around.
→ Systolic: pressure at peak of the contraction
→ Diastolic: pressure during ventricular relaxation
Heart: Tissues
Listed from outer to inner.
Epicardium: Mainly made of connective tissue
Myocardium: Mainly made up of Cardiac muscle tissue
Endocardium: Mainly made of squamous epithelial.
Heart: Chambers
There are four chambers
Two superior Atria (Low Pressure)
→ They receive the blood after it has travelled through the body
→ Thin-walled due to low pressure
and
Two inferior Ventricles (High pressure)
→ Discharging chambers that push the blood back out.
→ Thick-walled due to high pressure
Each has its own one-way valve.
Heart: Pumping the blood
Pulmonary Circulation loop
1) Starts in the right ventricle. It pumps it through the pulmonary trunk (the only artery that carries deoxygenated blood) into the lungs to exchange CO2 for Oxygen
2) Then the pressure imbalance makes the blood want to go to a lower pressure area. Then it enters the left atrium via pulmonary veins.
Systemic Loop
3) Then the blood goes to the left ventricle via the one-way valve. The left ventricle contracts and the blood flows through your aorta to the rest of your body.
4) After the oxygen has been distributed, the blood enters the right atrium via the superior and inferior vena cava veins. Then the blood goes to the right ventricle and the cycle restarts.
Heart: How it beats
There are pacemaker cells that generate their own pulse of electricity through the Intrinsic Cardiac Conduction system (Hearts wiring). Think of them as the brain of the heart, they control the beats of the heart!
Blood Vessels: Functions
1) Deliver oxygen and nutrients to the cells
2) carry away waste products
3) part of maintaining blood pressure and body temperature
Blood vessels: Parts
Lumen: Inside of the blood vessel where all the blood flows
Tunica Intima: Made of Endothelium(squamous epithelium tissue), connective tissue and internal elastic membrane.
→ The endothelium secretes mucus to make sure that the blood can flow without friction
Tunica Media: Made of smooth muscle cells and protein elastin.
→ Responsible for contraction (Vasoconstriction) or expansion (Vasodilation)
→ The smaller the diameter of the blood vessel, the harder it is for the blood to move through it. This is helpful to slow down the blood and lower the pressure so that it does not burst the smaller blood vessels.
Tunica Externa: Made of loosely woven collagen fibre
The aorta has the most elastin of any blood vessel.
Blood: Red Blood Cells
→ aka Erythrocytes → Carries carbon dioxide and oxygen → Makes of 45% of the total blood volume → Don't have nucleus → 97% hemoglobin
Blood: White blood cells
→ aka Leukocytes
→ Defend the body from toxins and harmful bacteria.
Blood: Platelets
→ Help with blood clotting
→ Makes less than 1% of the blood
