Cardiovascular & Respiratory System Test Review Flashcards
Components and Function of Cardiovascular System
Composed of:
- Heart, blood vessels, blood
Functions:
- Delivery of O2, fuel, and nutrients, to the tissues of the body
- Removal of CO2 and waste products from the tissues
- Maintenance of a constant body temperature (thermoregulation)
- Prevention of infection (immune function)
Layers of the Heart
- Pericardium (protective sac)
- Epicardium (lies against pericardium)
- Myocardium (below epicardium, muscle layer)
- Endocardium (tissue inside)
What is the heart considered to be?
“Double pump.” Divided into the right and left heart; separated by the interventricular septum
Right Heart (Main Function)
Pumps deoxygenated blood (darker red) from the body to the lungs (pulmonary circulation)
Left Heart (Main Function)
Delivers oxygenated blood (bright red) from the lungs to the rest of the body (systemic circulation)
Heart Valves
4 valves in the heart ensure that blood flows along the proper path;
- Opening and closing the 4 chambers
- Consist of unidirectional flaps (AKA cusps or leaflets) that cause blood to flow in 1 direction only, preventing back flow
- From the atria into the ventricles, and out the ventricles through the vessels of systemic or pulmonary circulation
- Attached to the special muscular extensions of the ventricle walls (papillary muscles) by strands of tissue called the chordae tendinae
Pulmonary Semilunar Valve
Tricuspid, found between the right ventricle & pulmonary artery, prevents back flow from the PA into the RV
Aortic Semilunar Valve
Tricuspid, found between left ventricle & aorta, prevents back flow from the A into the LV
AV Bicuspid (Mitral) Valve
Bicuspid, found between the left atrium and left ventricle, prevents back flow from the LV to the LA
AV Tricuspid Valve
Tricuspid, found between the right atrium and right ventricle, prevents back flow from the RA into the RV
Pathway of Blood through the Heart
Superior and Inferior Vena Cava
Right Atrium
Tricuspid Valve
Right Ventricle
Pulmonary Semilunar Valve
Pulmonary Artery
Lungs
Pulmonary Veins
Left Atrium
Bicuspid (mitral) Valve
Left Ventricle
Aortic Semilunar Valve
Aorta
Arteries
Arterioles
Capillaries
Venules
Veins
Path of Electrical signal through the Heart
- SA node
- Atria
- Bottom of atria to the AV node
- Down ventricular septum
- Bundle of His
- Right and Left bundles
- Purkinje fibers
- Myocardium
SA Node
Region of tissue found in the right atrium. Heart’s “pacemaker” because it is the location where electrical signals are initiated
Internodel Pathways
What the electrical signal travels through in the atria
AV Node
Located at the bottom of the atria which transmits the signal into the ventricles.
Bundle of His
Region of tissue that separates the 2 ventricles and spilts to form the right and left bundle branches
Purkinje Fibres
Branched fibres that carry the electrical signal to the ventricles
Arteries
Blood vessels that carry blood away from the heart. In systemic circulation, arteries carry oxygenated blood from the left side of the heart towards body tissues. In pulmonary circulation, arteries carry deoxygenated blood from the right side of the heart towards the lungs.
Arterioles
The vessels in the blood circulation system that branch out from arteries to capillaries, where gas exchange occurs. Surrounded by smooth muscle, arterioles are the primary site of vascular resistance (smaller than arteries)
Capillaries
The smallest of the blood vessels and help to enable the exchange of water, oxygen, carbon dioxide, and other nutrients and waste substances between blood and the tissues.
Venules
Small thin-walled extensions of the capillaries that lead into the veins, which return blood to the heart from another trip throughout the vascular system.
Veins
Blood vessels that carry blood toward the heart. In systemic circulation, veins carry deoxygenated blood towards the right side of the heart from body tissues. In pulmonary circulation, veins carry oxygenated blood toward the left side of the heart from the lungs.
Pathway of the Vascular System
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
3 Ways: Skeletal Muscle Pump
- The first system used to assist in the return of blood in the veins to the heart.
- A general term used to describe how, with each contraction of skeletal muscle, blood is pushed or massaged that muscle.
- Occurs because of the one-way valves found in the veins. Each contraction of a muscle compresses the veins within or around the muscle, increasing pressure within that vein. The increase in pressure moves the blood along, and because of the one-way valves, the only direction the blood can travel is back toward the heart
3 Ways: Thoracic Pump
- The second system used to assist in the return of blood in the veins to the heart.
- Related to breathing. With each breath taken by the respiratory system, pressure in the chest cavity is very low for a few short seconds, while the pressure in the abdominal cavity increases.
- Creates a difference in pressure between the veins in these 2 body cavities, and pushes blood from the veins in the abdominal cavity into the veins in the thoracic cavity, because of the one-way valves found in the veins.
3 Ways: The Nervous System
- The final system used to assist in the return of blood in the veins to the heart.
- At times when cardiac output needs to be increased, such as during exercise, the nervous system sends a signal to the veins, causing them to slightly constrict (this response is known as vasoconstriction). The slight constriction helps to return more blood to the heart.
Components of blood: Plasma
The fluid component of blood. It is composed of mostly water and makes up 55% of blood. Within the plasma, there are many different dissolved substances, such as nutrients, proteins, ions, and gasses.
Components of blood: White Blood Cells (leukocytes)
Make up less than 1% of blood and are an important part of the body’s immune system (fights off disease). Platelets are fragments of cells found in blood and play an important role in the regulation of blood clotting
Components of blood: Red Blood Cells
Make up 45% of blood, with the most abundant blood cells being the red blood cells or erythrocytes.
Erythrocytes are specialized cells that transport O2 and CO2 in the blood. They contain a protein called hemoglobin, which can bind O2 and CO2. Hemoglobin gives blood the ability to transport and deliver O2 to the tissues and removes CO2 from the lungs.
Cardiac Output (Q)
The amount of blood the heart pumps per minute
What is Hemoglobin?
A protein which can bind O2 and CO2. Hemoglobin gives blood the ability to transport and deliver O2 to the tissues and removes CO2 from the lungs. Found in erythrocytes
Stroke Volume (SV)
The amount of blood pumped from the left ventricle in a single beat
Heart Rate (HR)
The number of times the heart beats per minute.
Blood Pressure
The force exerted by the blood against the walls of the arteries.
Systolic Blood Pressure
Refers to the pressure observed in the arteries during the contraction phase (eg. 120 mmHg). This is the pressure measured in the arteries that is caused by the contraction of the heart.
Diastolic Blood Pressure
Refers to the pressure observed in the arteries during the relaxation phase of the heart (eg. 80 mmHg). This is the pressure measured in the arteries that is caused during the relaxation of the heart.
How does blood get redistributed during exercise?
Cerebal, Myocardial, Muscle, Renal, Digestive, Skin
Bradycardia
A decrease in heart rate and is one of the most easily observed adaptations that occur with training. It’s characterized by a heart rate of 60 beats per minute or less at rest.
Tachycardia
A heart rate of more than 100 beats per minute at rest.
How does training help the Cardio System?
Alterations in the Structure of the Heart
- Increases in ventricular volume and thickness of ventricular walls occur due to persistent increases in venous return during exercise
- Increase in ventricular volume = increase in SV
- Increase in ventricular wall thickness = increase in force of contraction of ventricle
- Both would lead to increases in SV and Q during exercise
How does training help the Cardio System?
Increase in # of Capillaries that Delivers Blood to the Myocardium
- Likely a response to the increase in O2 demand due to increase in work done by the heart during exercise
- Training may also lead to an increase in the diameter of coronary arteries, increasing the delivery of blood to the myocardium
How does training help the Cardio System?
Increase in Blood Volume
- Occurs within a few days of initiating training, and may see increases upward to 15% in plasma volume
How does training help the Cardio System?
Changes in Cardiac Output (Q) During Exercise
- Increases in plasma volume = increase in venous return = increase in SV & Q
- Increase in erythrocytes with continued training
- Decrease in resting heart rate and sub-maximal exercise heart rate
External Respiration
Involves exchange of gasses (O2 & CO2) within the lungs
Internal Respiration
Involves exchange of gasses (delivery of O2 & removal of CO2) at the tissues
Cellular Respiration
Cells using O2 to generate energy in mitochondria.
Conductive Zone: Structure
- Mouth and nose, larynx, trachea
- Primary and secondary bronchioles
- Tertiary and terminal bronchioles
Conductive Zone: Function
- Filters air as breath
- By the time air reaches the respiratory zone, it is at body temperature (37*C) and is almost completely saturated with moisture
- Protects sensitive tissue making up the respiratory zone
- Filters air that is taken in with each breath (the nasal cavity is lined with hairs to trap foreign bodies and prevent them from being inspired (breathed in))
Respiratory Zone: Structure
- Respiratory bronchioles
- Alveolar ducts
- Alveolar sacs (alveoli)
Respiratory Zone: Function
- Involved with the exchange of gasses between inspired air and the blood
- Alveolar sacs are found within the lungs and provide a large surface area for diffusion of gasses into and out of the blood
Inspiration & Expiration
In response to stimulation in the brain, at the start of a breath, the diaphragm contracts, pulling downward and enlarging the thoracic (chest) cavity. At the same time, the intercostal muscles contract, moving the chest cavity upward and outward, which also helps to enlarge the chest cavity. As the chest expands, the lungs expand with it. The pressure in the lungs becomes negative relative to the outside air. The lower air pressure causes air to rush into the lungs, which results in an inhalation (or inspiration) that equalizes this pressure differential.
Once the lungs are inflated with air, the chest muscles and diaphragm relax and recoil to their original positions. This compresses the lungs and forces air out of the airways (exhalation or expiration)
Ventilation (VE)
- The volume of air moved by the lungs in 1 minute (combo of inspiration & expiration)
- Influenced by 2 factors: Tidal Volume & Respiratory Frequency
Tidal Volume (VT)
- Volume of air in each breath
- At rest = approx.
0.5 L/breath - During exercise = approx. 3-4 L/breath
Respiratory Frequency (f)
- Number of breaths taken per minute
- At rest = typically 12 breaths/minute
5 Parts of Gas Exchange
- Breathing
- External Respiration
- Gas Transport
- Internal Respiration
- Cellular Respiration
Diffusion
The process responsible for the movement of gasses in the body and can be defined as the movement of a gas, liquid, or solid from a high concentration to low concentration through random movement. Only occurs if a difference in concentric exists, known as a concentration gradient
Oxygen (O2) Transport
Oxygen is absorbed in the lungs by hemoglobin in circulating deoxygenated red blood cells and carried to the peripheral tissues. There are 2 ways that O2 is transported within the blood:
- 2% dissolved within the blood plasma (~0.5 mL O2 /100mL of blood)
- Rest (98%) binds to specialized protein in erythrocytes (RBCs) called hemoglobin (referred to as oxyhemoglobin)
Various factors will affect the ability of O2 to attach to hemoglobin
- The relative amount of O2 attached to hemoglobin is termed the percent saturation of hemoglobin (SbO2%)
- Main factor affecting SbO2% is the PO2; the lower the PO2, the less O2 will bind to hemoglobin
Carbon Dioxide (CO2) Transport
CO2 in blood is moved into the alveoli and then exhaled from the body. There are 3 ways CO2 is transported in blood:
- 5-10% CO2 remains unchanged, dissolved in the blood plasma
- 20% binds to hemoglobin (on erythrocytes) forming carbaminohemoglobin when there is low concentrations of O2
- O2 in lungs is high which cause CO2 to be released from hemoglobin (diffuses into alveoli and is exhaled)
- 70-75% of CO2 transported through bicarbonate system
Respiratory Dynamics and the Response to Exercise: Pulmonary Ventilation (VE)
Is closely matched to the rate and/or intensity of the work being done. The increases in VE that occur with submaximal exercise can be divided into 3 phases;
- Phase 1 is termed the rapid on phase. During this phase, VE is increased at a very rapid rate, almost immediately upon the onset of the activity
- Phase 2 is characterized by a slower exponential increase from the rapid increase observed in Phase 1
- Phase 3 of the response is characterized by a levelling off of VE at a new steady-state level. The new steady-state level is predominantly determined by the intensity of the exercise and the level of fitness of the individual
Respiratory Dynamics and the Response to Exercise: External Respiration
Total gas exchange at the lungs is increased as a result of 2 main factors:
- The increase in VE
- The increase in blood flow to the lungs
The increase in gas exchange is closely matched to the increase in requirements of the working skeletal muscle. The increase in VE serves to maintain the necessary gradients in the partial pressures of both O2 and CO2, to maintain gas exchange.
Respiratory Dynamics and the Response to Exercise: Internal Respiration
Internal respiration involves the exchange of gasses at the level of the tissues. Essentially, the extraction of O2 at the tissues is increased
This occurs as a result of 4 main factors:
- An increase in PO2 gradient
- An increase in PCO2
- A decrease in pH
- An increase in temperature
Oxygen Deficit
- The amount of oxygen taken in during stressful exercise minus the amount of oxygen that would otherwise be required for steady-state aerobic exercise
- During this period, the working muscle most partially rely on metabolic systems that do not require O2
- These anaerobic systems make up the difference between and compensate for the “lag” in VO2, allowing the exercise to continue at the new workload
Ventilatory Threshold
A state in which ventilation increases much more rapidly than workload. It normally occurs at an exercise intensity that corresponds to 65-85% of VO2 max, depending on the individual’s level of fitness.
Lactate Threshold
It is possible to measure blood lactate repeatedly during incremental exercise. Eventually, a point is reached where blood lactate concentrations begin to increase; this point is referred to as the lactate threshold.
VO2 Max
- Maximum volume of O2 in millilitres that the human body can use in 1 minute, per kilogram of body weight, while breathing air at sea level
- VO2 can be determined using a computerized metabolic cart system (indirect calorimetry). This system measures the amount of air expired over time and the concentration of O2 in the expired air
Vessels: Biggest to Smallest
Aorta, arteries, arterioles, capillaries, venules, superior and inferior vena cava.
