CIRCULATORY AND RESPIRATORY SYSTEMS Flashcards
What is the circulatory fluid in an open circulatory system?
Hemolymph (blood + interstitial fluid)
What is the circulatory fluid in a closed circulatory system?
Blood
Which circulatory system has a higher pressure and is more effective at transport?
A closed circulatory system
What are the 3 components of a circulatory system?
- Circulatory fluid
- Set of interconnected vessels
- Muscular pump
How do organisms without a circulatory system function?
Their body tissues are thin enough to absorb O2, and nutrients simply diffuse from the digestive system to other tissues
What is the function of arteries?
Arteries carry O2-rich blood away from the heart, and are thick to accomodate for the high pressure of blood pumped from the heart
What is the function of veins?
Veins carry O2-poor blood to the heart and are thin and have valves
What is the function of capillaries?
Capillaries are the site of gas exchange
What is the function of the atrium?
The atrium receives blood
What is the function of the ventricle?
The ventricle pumps blood
What are the 3 similar layers between arteries and veins?
- Endothelial lining
- Smooth muscle
- Connective tissue
What is absent where diffusion/exchange occurs in capillaries?
Smooth muscle
What is the process for single circulation?
In single circulation, blood collects in the artium and moves to the ventricle, where it is then pumped throughout the body, passing through 2 capilary beds before returning to the heart
What is the process for double circulation?
In double circulation, there are 2 circuits of blood flow and pumps are combined into 1 organ to simplify coordination of the pumping cycle
What 2 circuits are present in double circulation?
- Pulmonary circuit
- Systemic circuit
What is the function of the pulmonary circuit?
The pulmonary circuit is located on the right side of the heart and pumps O2-poor blood to capillary beds of gas exchange tissues
What is the function of the systemic circuit?
The systemic circuit is located on the left side of the heart and pumps O2-rich blood from gas echange tissues in the lungs to capillary beds in organs and tissues
What happens to blood flow when there is a decrease in vessel diameter?
Veocity decreases because of the higher resistance and larger-cross sectional areas
What is blood pressure?
Blood pressure is the hydrostatis pressure that blood exerts against vessel walls
What determines blood pressure?
- Cardiac output - volume moved out per unit of time
- Peripheral resistance via arteriole constriction
What are the 2 types of blood pressure?
- Systolic pressure - highest pressure during cardiac contraction
- Diastolic pressure - lowest pressure during cardiac relaxation
In what direction does blood from?
Blood flows from high pressure areas to low pressure areas
How does vasodilation regulate blood pressure?
Vasodilation opens the vessels, decreasing blood pressure
How does vasoconstriction regulate blood pressure?
Vasoconstriction narrows the vessels, increasing blood pressure
What system is in charge of fluid return?
Lymphatic system
Where does the lymphatic system drain lymph collected at the venous ends of capillary beds
Large veins in the neck
What are lacteals?
Lacteals are special lymph capillaries which collect digested fats
What is gas exchange?
Gas exchange is the intake of O2 and the release of CO2
What is a respiratory medium?
A respiratory medium is the source of O2 (e.g. air, water)
What is a respiratory surface?
A respiratory surface is the site of gas exchange
What increases the rate of diffusion?
- Larger surface area
- Shorter path for diffusion
What must an effective respiratory surface have?
- Large surface area
- Thin permeable surface
- Moist exchange surface
What is negative pressure breathing?
Negative pressure breathing is the pulling of air into the lungs
What happens when the diaphragm contracts?
The volume of the lungs increases and air pressure is lowered, allowing for inhalation
What happens when the diaphragm relaxes?
The volume of the lungs decereases and air pressure is increased, forcing air out of the lungs (axhalation)
How is our rate of breathing controlled?
The medulla uses pH of fluid in which it is bathed as an indicator of blood-CO2 levels
When CO2 levels are high, there is an increase in H+ (a drop in pH), so the medulla sends a message to increase depth and rate of breathing to bring CO2 levels back down
What is partial pressure?
Partial pressure is the pressure exerted by 1 gas in a mixture
In what direction do gases diffuse?
Gases diffuse down concentration gradients, from areas of higher partial pressure to those of lower partial pressure
What is a respiratory pigment?
A respiratory pigment is a protein which increases the amount of O2 that blood can transport
What happens when O2 binds to 1 subunit of hemoglobin?
There is an increase in affinity of other subunits for O2
What happens when O2 unbinds from hemoglobin?
Hemoglobins affinity for O2 decreases
What is Bohr’s shift?
Bohr’s shift occurs when CO2 reacts with H2O to form H2CO3, decreasing pH and decreasing hemoglobins affinity for O2
What are different pathological changes which affect gas exchange in alveoli?
- Decrease in alveolar surface area
- Emphysema (chronic smokers)
- Increase in alveolar membrane thickness
- Scar tissue from fibric lung diseases
- Increase in diffusion distance
- Pulmonary edema
What is asthma?
Asthma is the chronic inflammation of the bronchial tubes that causes swelling and narrowing of airways
What are symptoms of asthma?
- Shortness of breath
- Wheezing
- Coughing
- Chest tightness
What are the 2 goals for asthma treatment?
- Control airway inflammation using corticosteroids
- Prevent airway thickening using bronchiodilators
What is emphysema?
Emphysema is the decrease in cilia from cell lining of airways due to long-term exposure of cigarette smoke
What is chronic obstructive bronchitis?
COB is difficult breathing as a result of irritated and inflammed airways lined with thick mucus
