lesson 7 - function of circulation Flashcards
What is the circulatory system?
A vascular system that controls the movement of fluid by muscle movements following a specific pattern
Main functions of the circulatory system?
1.It transports gases (from the respiratory system), nutrient molecules, waste
materials (ex. urea from the digestive system), and hormones from the endocrine system
- It regulates internal temperature
- Protects against blood loss, pathogens, and toxic substances
Three components of the circulatory system
- Heart: moves fluid
- Blood vessels: conduct fluid from one area to another (e.g. veins and arteries)
- Blood: specialized fluid
2 Types of Circulation
- Open circulatory system: the route taken BY the blood, WITHIN the heart (ex: insect)
- Closed circulatory system: the route taken by the blood FROM the heart TO the lungs, and BACK (ex. earthworm)
Functions of blood
- Transports oxygen, water, nutrients, and other chemicals to your cells
- Removes waste products from the tissues and delivers them to the areas where they can be removed from your body
- Helps to regulate body temperature, fight infection, and heal wounds
What is vasodilation?
An increase in blood flow by widening or dilating the vessels. It helps the body to lose heat more rapidly
What is vasoconstriction?
A decrease in the flow of blood by narrowing or constricting the blood vessels near the surface of the skin. It reduces the amount of heat that is dissipated from the skin, and helps the body to conserve heat.
What is in our blood?
- Plasma (Water + dissolved gases + proteins + sugars + vitamins + minterals + waste products)
- Solid parts (RBC, white blood cells, platelets)
What is plasma made up of?
92% water, 7% blood proteins, 1% organic/inorganic ions (ex. sodium, potassium, chloride, bicarbonate)
The major blood proteins
Fibrinogens, globulins, and albumins
What do fibrinogens do?
Fibrinogens assist in clotting bloodW
What do globulins do?
Globulins are types of antibodies
What do albumins do?
Albumin helps balance osmotic pressure and carry hormones
What is the composition of blood?
55% Plasma, 4% White blood cells & platelets, 41% RBC’s
Functions of RBC/Erythrocytes
Transports oxygen to cells, transports carbon dioxide away from cells, and has iron in the hemoglobin protein which binds to oxygen (They do NOT contain nuclei)
Functions of white blood cells/leukocytes
They engulf and destroy pathogens and produce antibodies (They contain nuclei)
How do platelets work, and how is fibrin formed?
Platelets are formed from fragments of bone marrow cells.
When blood vessels rupture, chemicals get released and attract platelets. The platelets then rupture and break open and releases chemicals which mix with the chemicals from the plasma, creating an enzyme called thromboplastin. Thromboplastin reacts with thrombin in the presence of calcium, and thrombin will then react with fibrinogen (plasma protein) which results in the production of an insoluble protein called fibrin.
Fibrin forms into a mesh that traps RBC’s and platelets and forms a blood clot.
Three major types of vessels
Arteries, veins, capillaries
Arteries have highly elastic walls. What does the elasticity do?
The elasticity allows arteries to expand and snap back during the contraction and relaxation of ventricles. The expansion and contraction keeps the blood flowing in the right direction
Tell me about veins (hint: walls, elastic, valves)
They have thinner walls in comparison to the arteries, though aren’t as elastic and can’t contract to move blood back to the heart like arteries do.
Veins have one-way valves that prevent blood from flowing backwards; this is especially important in the legs because they make sure the blood flows upwards to your heart, against the downward pull of gravity
What are capillaries?
The smallest blood vessels which are spread throughout the body in a fine network. They are a single layer of cells and the average diameter of a capillary (8μm) is JUST large enough for the largest blood cells to pass through in a single file
Where does blood flow from?
The heart –> large arteries –> smaller arteries –> aterioles –> capillaries –> venules –> smaller veins –> larger veins –> back to heart
Three types of circulation
Cardiac, pulmonary, systemic
Explain cardiac circulation
Cardiac circulation – the route taken by the blood within the heart
Explain pulmonary circulation
Pulmonary circulation – the route taken by the blood from the heart to the lungs and back
Explain systemic circulation
Systemic circulation – the route from the heart to the rest of the body and back
Valves in the heart
Atrioventricular and semilunar valves
Atrioventricular valves
Right atrium 🡪 tricuspid valve 🡪 right ventricle
Left atrium 🡪 bicuspid/mitral valve 🡪 left ventricle
Semilunar valves
Between ventricle and large arteries (the pulmonary & aortic valve)
Right atrium receives __ blood from superior/inferior vena cava
deoxygenated
Superior vena cava takes blood from __, __, and __
Inferior vena cava takes blood from __ __ __
- head, chest, and arms
- all other parts
Right ventricle pumps blood to __ __ that feed into the lungs
pulmonary arteries
Pulmonary arteries are the ONLY arteries that..
contain deoxygenated blood
Pulmonary veins bring ___ blood to the left atrium
oxygenated
Left ventricle pumps blood into the largest vessel: the __, which brings blood to the rest of the body
aorta
