Cardiovasuclar Flashcards
What system hold most of the blood and why?
The venous system, serves as a reservoir, releasing more blood into circulation when needed (e.g., during exercise)
How do arteries and veins differ regarding blood flow?
Unlike arteries that resist blood flow, veins expand to hold extra blood
How do lower limbs return blood to the heart?
Venous pressure is low, so in lower limbs, veins pass between skeletal muscle groups which provide contractions to help move blood back (skeletal muscle pump)
How do the abdominal and thoracic regions return blood to the heart?
In abdominal and thoracic regions breathing+contraction of the diaphragm+pressure in the abdomen from breathing squeezes the veins and helps blood return to the heart
What structural feature is present in the tunica media of the aorta and large arteries?
Numerous layers of elastin fibers between smooth muscle cells.
When do large elastic arteries expand?
when pressure of blood rises when ventricles contract
What drives blood during diastole (when heart is at rest)
Elastic recoil
How many capillaries in body?
over 40 billion
What is vasoconstriction and vasodilation?
Vasoconstriction - Decreases blood flow to the capillary bed
Vasodilation - Increases blood flow to the capillary bed
What are capillary walls like?
Capillary walls have a single layer with no smooth muscle or connective tissue, allowing easy blood and tissue exchanges
What occurs at the arterial end of capillaries?
Blood pressure pushes oxygen, nutrients, and small molecules out to surrounding tissue.
What occurs at the venous end of capillaries?
Osmotic pressure pulls waste and carbon dioxide back into the capillary.
What connects the nasal cavity to the larynx?
The pharynx which is a muscular passage that links connects to the nasal cavity and then connects to the larynx
What happens in the larynx?
Air is diverted to lungs, food diverted to stomach, and contains vocal cords
What do pores and lung tissues allow?
Through pores, air can pass from one alveolus to another
What happens to the chest and diaphragm when breathing in?
Chest expands, Diaphragm contracts
What is lung compliance?
Lung compliance is the change in lung volume per change in transpulmonary pressure (dV/dP).
Higher compliance means greater expansion at a given pressure.
What does lung disease cause to lungs?
Lung disease reduces compliance, making expansion harder.
What happens to chest and diaphragm when breathing out?
Chest contracts, diaphragm relaxes.
Lungs shrink when tension is released, requiring elasticity which is the ability to return to their original size after stretching.
Why are lungs elastic?
Lungs are elastic due to high elastin protein content
What does lungs being attached to chest wall do?
maintains constant elastic tension. This tension increases during inhalation as the lungs stretch and decreases during exhalation due to elastic recoil.
What attaches the lung to the chest wall?
Pleural membranes
What does pleural membrane secrete?
Secretes mucus rich pleural fluid into plural space
What are two things that pleural fluid do?
holds the two pleural membrane layers together, also the lubricant that allows lungs to slide within thoracic cavity as they inflate and deflate
What is a case where surface tension needs to be reduced and what happens?
Fluid in alveolar creates surface tension which can cause alveolar collapse during exhalation.
Type II alveolar cells secrete surfactant which reduces surface tension
What are the 4 categories of lung volumes?
Tidal volumes: Air inhaled or exhaled in normal breath
Inspiratory reserve: Extra air inhaled beyond tidal volume during forced breathing
Expiratory reserve : Extra air exhaled beyond tidal volume during forced breathing
Residual volume: Air left in the lungs after maximum exhalation
What are the 4 categories of lung capacities?
Total lung capacity: Air in lungs after maximum inhalation
Vital capacity: Maximum air exhaled after maximum inhalation
Inspiratory capacity: Maximum air inhaled after normal exhalation
Functional residual capacity: Air left in lungs after normal exhalation
What does hemoglobin contain and where is it present?
Contains iron and is present in the cytoplasm red blood cells
What does hemoglobin combine with and release?
O2
What does hemoglobin act as regarding O2?
Acts as an O2 shuttle from the lungs to body tissues
What does hemoglobin do regarding CO2?
Hemoglobin carries CO2 from tissues to lungs
In the lungs, what does high pH promote?
O2 binding
In tissues, what does low pH cause?
O2 release
What happens in the lungs regarding CO2 and pH?
In the lungs, CO2 moves from blood to alveoli, lowering blood CO2 and increasing pH
What happens in tissues regarding CO2, O2 and pH
In tissues, high CO2 from cell activity lowers O2 and lowers pH
What does plasma acidity affect?
Plasma acidity, influenced by CO2, affects oxygen binding to hemoglobin
