Circulatory System Extended (Blood) Flashcards
What is cardiac output, and what does it indicate?
- amount of blood pumped by the heart (mL/min)
- indicates level of oxygen delivered to the body
What is a heart rate?
Number of heartbeats per minute
What is stroke volume?
- Amount of blood forced out with each heartbeat
- how readily the heart fills and empties basically
How do you calculate cardiac output?
Heart rate x stroke volume
What is the average cardiac output?
- 4900 mL/min
70bpm) x (70mL/beat
What do fitter people have in terms of cardiac output?
- lower resting heart rates and higher stroke volume to maintain an average cardiac output
Why does cardiovascular activity help the heart?
- regular cardiovascular activity strengthens and enlarged ventricles, making the heart more efficient
What is maximum heart rate?
- highest heart rate attained during all-out physical effort
- decreases with age
After exercise, what do fitter people have?
- they have a shorter recovery time
- meaning shorter time to regain a resting heart rate after physical activity
What type of tissue is blood? why?
- connective tissue because it essentially links all body parts, cells, organs, etc.
- also a fluid tissue (plasma)
What is plasma, and what percentage does it make up in the blood?
- fluid portion of blood
- 55% of blood volume
What is the solid portion of blood? What percentage does each type take up in the blood? where are they formed?
Formed portion is cells and takes up 45% of blood volume
- 44% RBC
- 1% white blood cells and platelets
- solid portion is produced in bone marrow in bones
What are red blood cells also called, and what shape do they have? How many of them generally?
- erythrocytes
Biconcave disc-shaped - most numerous of blood cells
What are red blood cells specialized for? How much can it carry?
- specialized for oxygen transport
- capacity depends on number of RBCs and amount of haemoglobin (protein) in each RBC
Note: (The more hemoglobin and blood cells, the more a persons blood can carry oxygen)
What does hemoglobin contain?
- iron
- it’s an iron-containing respiratory pigment
How do red blood cells transport oxygen?
- hemoglobin chemically binds oxygen to transport it (oxyhemoglobin)
- releases oxygen by diffusion to body
What else can hemoglobin carry? And why do they have so much room?
- can carry some CO2 waste (and H+)
- RBC have no nucleus for more room (for oxygen)
What happens if a person has too few red blood cells or too little hemoglobin?
- results in anemia
- symptoms include paleness, fatigue
What are white blood cells also called?
- leucocytes
What do white blood cells do?
- part of body‘s response to infection
Generally how many white blood cells in the body? and what structure do they have?
- amount of white blood cells can double when body is infected
- have nuclei and appear colourless
What are the three types of white blood cells?
Granulocytes, monocytes. Lymphocytes
What do granulocytes and monocytes do?
- engulf and destroy foreign bodies in the blood (phagocytosis)
- monocytes can specialize to become macrophages that engulf bacteria by phagocytosis and destroy them
—> can leave bloodstream when necessary
How do macrophages move?
- move by amoeboid movement (unicellular I believe)
What do lymphocytes do?
- produce antibodies (marker proteins)
- Allows for pathogen detection and destruction
What are platelets? what dont they have?
- cell fragments released from bone marrow
- no nuclei
What do platelets do?
- Play a key role in clotting blood
- prevents excessive blood loss after injury
How do you platelets work to prevent blood loss?
- Platelets collect at injury site and rupture, releasing chemicals that combine with other components to produce enzyme thromboplastin
- A cascade of enzyme-catalyzed reactions leads to production of fibrin, proteins forming a mesh that blocks blood loss
- A clot is then formed as blood cells are trapped
What is suspended in plasma?
- blood cells are suspended in this liquid for flow
What does plasma contain?
- water plus dissolved gases, proteins, sugars, vitamins, minerals, hormones, and wastes
What does plasma play a role in? And how?
- carbon dioxide transport
1. CO2 dissolves in water, forming carbonic acid in cytoplasm of RBCs
2. H2CO3 diffuses out of RBCs into plasma as bicarbonate ions (HCO3-)
3. CO2 carried to lungs by blood for gas exchange
What are the two functions of the blood?
Transport and regulation
How does blood aid in transport generally?
- pathway for distributing materials and energy
How does blood play a role in the digestive system? Add some absorption too
- blood absorbs nutrients from the small intestine (capillaries of the villi)
- ## absorbs other materials made in body cells, such as glucose, amino acids
How does blood aid in the respiratory system?
- transports chemicals and gases to and from respiratory system
- For example, oxygen to body cells
How does blood aid in the excretory system in regards to transportation?
- blood carries wastes from body cells to kidney for filtering and excretion
- for example, uric acid, mineral ions
How does blood aid in the endocrine system in terms of transportation?
- Chemical messengers transported from production sites to target cells through blood
Why is blood called a connective tissue?
- It connects many cells together and systems together
What is homeostatic regulation?
- The body attempts to maintain relatively constant interior environmental conditions
- Blood plays an important role
How does blood play a role in homeostatic regulation of temperature?
- blood transports heat
- blood taken closer to the skin surface lets off heat
- blood retained in the body’s interior conserves heat
- Greater heat gradient equals more heat loss
What is the heat gradient? Own definition
Difference in temperature between skin and external environment
What is vasodilation and what happens in it?
- expansion of blood vessel diameter
- exterior blood vessels dilate to let in more blood in order to let heat dissipate (disappear)
What is vasoconstriction and how does it occur?
- decrease in blood vessel diameter
- Exterior blood vessels constrict to keep blood and warmth in the body’s core
What does Vaso refer to?
Blood vessels
How does vasodilation and vasoconstriction affect blood pressure?
- vasodilation lowers blood pressure
- vasoconstriction increases bp
Does exercise prompt vasodilation or basal constriction and why?
- vasodilation in order to increase blood supply to tissues that need it (and let off excessive heat)
What substances promote vasodilation?
- alcohol and nicotine when the body does not necessarily need it
Ex. Drunk people will get colder on a winter night
What does the countercurrent heat exchange system do?
- maintain steady body temperature
Conserve or give off (cool down) heat when necessary
How does the countercurrent heat exchange system work?
- warm blood from the core exchanges heat with cooler blood returning to core to conserve heat and maintain temperature of core
- blood can travel through a surface vein to expel excessive heat (has an option)
How do you capillaries/capillary beds play a role in circulation?
- capillary beds fill the body between artery and vein branches
- blood passes through capillaries when the blood is needed
- Otherwise, it can pass through an arteriovenous shunt to bypass the capillaries
What do precapillary sphincters do?
Control blood flow into capillaries
What blood pressure do capillaries have?
BP is in between that of arteries (highest) and veins (lowest)
- blood pressure decreases from arteries to capillaries to veins to ensure blood flow
Why is blood flow the slowest in capillaries?
To allow for diffusion to occur
What is interstitial fluid?
- fluid that surrounds all body cells
- also known as extracellular or tissue fluid
What does interstitial fluid do?
- nutrients and wastes must pass between blood and cells through this fluid
- nutrients and oxygen diffuse down concentration gradient from blood to institutional fluid to cells
- Wastes flow down concentration gradient from cells to interstitial fluid and blood
