Chapter 13 - Circulatory and Respiratory Systems Flashcards
What is the human cardiovascular system composed of?
1) Muscular, four chambered heart
2) Blood vessels
3) Blood
Describe the movement of blood:
- Blood is pumped into the aorta which branches into a series of arteries
- Arteries branch into arterioles and then into microscopic capillaries
- Exchange of gases, nutrients, and cellular waste products occur via diffusion across capillary walls
- Capillaries converge into venues and back into veins that carry deoxygenated blood back toward the heart
- From the heart the blood is pumped into the lungs to exchange CO2 for O2
- Oxygenated blood returns to heart to be pumped once more
What does the heart do?
It is the driving force of the circulatory system
What does the right vs. left side do?
Right side:
- Pumps deoxygenated blood into pulmonary circulation (toward lungs)
Left Side:
- Pumps oxygenated blood into systemic circulation (throughout body)
What are the upper and lower chambers called? Describe each:
Upper = Atria
- Thin-walled
Lower = Ventricle
- Muscular
- Left > right muscular because it must generate force that propels systemic circulation and pumps against higher resistance
What is a result of increased systemic resistance?
Left ventricle becomes hypertrophied (enlarged) which can lead to congestive heart failure and other cardiovascular diseases
Describe the flow of blood through the heart:
- Blood returns from the body through the right atrium
- Through the tricuspid valve into the right ventricle
- Through the pulmonary semilunar valve into the pulmonary arteries to the lungs
- Blood runs from lungs through pulmonary veins into the left atrium
- Through the mitral valve into the left ventricle
- Finally, out through aortic semilunar valve into systemic circulation
Where is the atrioventricular valve located? What does it do?
Located between the atria and ventricles on both sides of the heart
- Prevents back flow of blood into the atria
Where is the tricuspid valve located? How many cusps?
Located on the right side of the heart
- Has 3 cusps
Where is the mitral valve located? How many cusps?
Located on the left side of the heart
- Has 2 cusps
Where are the semilunar valves located?
Located between the left ventricle and aorta and between the right ventricle and the pulmonary artery
What creates the “lub-dub” sound of the heart?
The successive closing of the atrioventricular and semilunar valves
How is the heart’s cycle divided?
Into 2 alternating phases:
1) Systole: Phase where ventricles contract, forcing blood out of the heart and into the pulmonary system
2) Diastole: Phase where cardiac muscle relaxation during which blood drains into all 4 chambers
Describe blood pressure:
- Systolic blood pressure measures the pressure in a patients blood vessels when the ventricles are contracting
- Diastolic blood pressure measures the pressure during cardiac relaxation
Define cardiac output:
Total volume of blood the left ventricle pumps out per minute
Cardiac Output = Heart Rate (beats/min) x Stroke Volume (V of blood pumped out of L-ventricle/contraction)
How is the heart rate controlled?
Cardiac muscles contract rhythmically without stimulation from nervous system, producing impulses that spread through its internal conducting system
Where does an ordinary cardiac contraction originate and is regulated by?
- How does the impulse spread?
- Where does the pulse arrive?
- How is the impulse carried?
- What does the strong contraction do?
The sinoatrial node (SA) which is a small mass of specialized tissue located in the wall of the right atrium
- Spreads impulse through both atria stimulating them to contract simutaneously
- Arrives ar atrioventricular node (AV) which conducts the impulse to the rest of the heart, allowing time for atrial contraction and for ventricles to fill with blood
- Impulse carried through bundle of His (AV bundle) which branches to the L/R and through Purkinje fibers located in the ventricular walls to stimulate a strong contraction
- Forces blood out of the heart
What modifies the rate of the heart? How?
ANS
- PNS innervates heart via vagus nerve to decrease HR
- SNS innervates heart via cervical and upper thoracic ganglia to cause increases in HR
- Adrenal medulla exerts hormonal control via epinephrine recreate to increase HR
What are the 3 types of blood vessels? Describe each:
1) Arteries
- Thick walled, muscular, elastic vessels the support oxygenated blood flow away from the heart
- Except for the pulmonary artery (deoxygenated blood from heart to lungs)
2) Veins
- Thin walled, inelastic vessels that carry deoxygenated blood toward the heart
- Except for the pulmonary vein (oxygenated blood from lungs to heart)
- Depends on compression from skeletal muscle
- At odds with gravity (valves)
3) Capillaries
- Smallest diameter (RBC single filed)
- Single layer of epithelial cells
- Exchanges gas, nutrients, and waste
What is the lymphatic system?
Second circulatory system; transports excess interstitial fluid (lymph) to the cardiovascular system to keep fluid in the body constant
What is the smallest lymphatic vessel? What do they do?
Lacteals
- Collect fats in the form of chylomicrons from villi in the small intestine and deliver to the blood stream, by passing the liver
What are lymph nodes?
Swellings along lymph vessels containing phagocytic cells (lymphocytes) that filter the lymph, removing and destroying foreign pathogens and particles
On average, how much blood does the human body contain? What are the percentages of the liquid and cellular components?
4-6L
- Liquid (55%) and cellular (45%)
What are the cellular components of blood?
Erythrocytes, leukocytes, and platelets
What is plasma? What does it consist of?
The liquid portion of blood
- Aqueous mixture of nutrients, salts, respiratory gases, wastes, hormones, and blood proteins
What are leukocytes?
Known as WBC which are larger than erythrocytes and serve to protect
What are platelets? What inhibits platelet formation?
Cell fragments that lack nuclei and are involved in clot formation
- Drugs can inhibit platelet formation or adhesion to decrease clot development
What are erythrocytes? How much hemoglobin does one RBC contain and how many O can it bind?
Known as RBC which are the oxygen carrying components of blood
- Contains 250 million hemoglobin molecules that bind 4 molecules of oxygen
What is the shape of a RBC? Why?
Concave
- Increased SA
- Flexibility
Where are RBC formed and stimulated by? What do they lose in the bone marrow?
Production in the bone marrow is stimulated by erthyropoietin (made in kidneys)
- They lose their nuclei, mitochondria, and membranous organelles in the bone marrow
What is the life span of a RBC? How are they destroyed?
A mature RBC will circulate in the blood for 120 days
- Phagocytize by special cells in spleen/liver
What characteristic do erythrocytes have? What do they do?
Cell-surface proteins (antigens)
- They are macromolecules that are foreign to the host organism and trigger an immune response
What are the two major RBC antigen groups?
1) ABO Group
2) Rh Factor
Describe each blood type:
- Corresponding antigen
- Corresponding antibody
- Donates to
- Receives from
1) A
- A
- Anti-B
- A and AB
- A and O
2) B
- B
- Anti-A
- B and AB
- B and O
3) AB
- A and B
- None
- AB only
- All “Universal Recipient”
4) O
- None
- Anti-A and Anti-B
- All “Universal Donor”
- O Only
What is important during blood transfusions? Why?
That donor and recipient blood types are matched
- Avoid transfusion of RBC that will be rejected
What is Rh factor? What types? When is it important? Is it important during transfusions?
Another antigen that may be present on surface of RBC
- Rh+ (possessing) OR Rh- (lacking)
- Important during pregnancy
- Yes; Rejection
What are the 3 functions of the circulatory system?
1) Transport of Gases
- O2, CO2, Hemoglobin, etc
2) Transport of Nutrients/Wastes
- Amino acids, simple sugars, are absorbed
- Wastes products (CO2) and removed
3) Clotting
- Platelets that come in contact with exposed collagen of a damaged vessel released a chemical to signal neighbouring platelets to adhere together (platelet plug)
- Clotting factor is released (thromboplastin) with the aid of vitamin K and Ca to concert inactive plasma to fibrin which coats damaged area to trap blood cells to form a clot
- Clots prevent excessive blood loss and heals the damage
- Serum is left after blood clotting
What is Warfarin? What does it do?
Anti-coagulent that inhibits recycling of vitamin K
- Without this, clotting cycle is inhibited and less likely to form clots
Describe the respiratory system:
Air enters the lungs:
- Through nose, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli
Where does gas exchange occur?
Between the lungs and circulatory system
- Across the thin walls of alveoli
What happens after gas exchange?
Air travels back through the respiratory system and is exhaled
What else does the respiratory system do?
- Protect against infection, dehydration, and temperature changes
- Production of sound
- Regulation of body pH by regulating CO2 removal
What is ventilation? Purpose?
Process of air being inhaled and exhaled
- Taking in of O2 and eliminate CO2
What occurs during inhalation?
Diaphragm contracts and flattens, and external intercostal muscles contract which pushes the ribcage and chest wall up/out
- Phrenic nerves innervates diaphragm to contract/flatten
- Increases in volume = reduces pressure = lungs expand and fill with air
What occurs during exhalation?
Lungs and chest recoil to originate position after inhalation
- Diaphragm and external intercostal muscles relax and chest wall pushes inward
- Decreases volume = pressure increase = forces air out and lung deflate
What is surfactant?
Protein complex secreted by cells in the lungs to keep them from collapsing by decreasing surface tension in alveoli
How is ventilation controlled?
Regulated by neurons located in medulla oblongata
- When CO2 in blood rises = stimulation of increase ventilation
What is the primary goal of respiration?
Maintain proper concentrations of O, CO2, and H-ions
- Highly responsive to changes in the blood
What occurs with increased levels of CO2 and H-ions in the blood?
Stimulation of inspiratory/expiratory muscles of the lungs
What monitors oxygen blood levels?
Chemoreceptors
How does gas exchange occur during respiration?
Dense network of pulmonary capillaries surround alveoli
- Gas exchange occurs by diffusion across these capillary walls and alveoli; gas moves from higher PP to lower PP
- Oxygen diffuses from alveolar air into blood
- CO2 diffuses from blood into lungs
What is total lung capacity?
The maximum volume of air the lungs can hold
What is tidal volume?
The volume of air moved during a normal resting breath (less than lung capacity)
What is the inspiratory reserve volume?
The volume of air that could be additionally inhaled into the lungs at the end of a normal, resting inhalation
What is the expiratory reserve volume?
The volume of air left in the lungs at the end of a normal, resting exhalation
What is the vital capacity?
The volume of air moved during a maximum inhalation followed by maximum exhalation
What is the residual volume?
The amount of air left in the lungs after maximum exhalation
