HUMAN ANTOMY 2
· Explain how each of the following factors is important in maintaining MAP: a) stroke volume, b) heart rate, c) total peripheral resistance, and d) total blood volume.
*look back at notes*
Describe the capillary blood pressure (e.g., relative level). Explain the benefit of low blood pressure at the capillary beds.
- 35mmHg- 17mmHg BENIFITS - prevent the rupture by high pressure - capillaries are parable, so low pressure is good enough to cause filtration
Explain the importance of venous valves in the one-way flow of blood back to the heart.
- allows pooling blood to not go backwards - lead to varicose veins( superficial veins susceptible often in lower body increased size due to broken valves)
Describe the lymphatic system and lymphatic vessels.
-conssist of two semi-independent parts - lymphatic vessels: return excessive tissue fluid and lead proteins to bloodstream -lymphatic nodes and organs: house phagocytes and lymphocytes; boys defense
State the functions of the respiratory system.
-provide oxygen -eliminate carbon dioxide
· Describe the four processes in respiration.
1) pulmonary ventialtion 2) extange of O2 and CO2 between air in the alvoli and blood 3)transport of O2 and CO2 between lungs and tissues 4) exchange of O2 and CO2 between the blood and the tissues
· Describe the forms in which carbon dioxide is transported in the blood and state the relative amount carried as each form.
1. Dissolved in plasma (7-10%) 2. Bound to amino acids of Hb (20-23%); not compete with O2. 3. As HCO3- (~70%)
Describe the venous blood pressure (e.g., relative level).
15mmHG-0mmHg -steady -pressure gradient is too low to promote enough venous return skeletal muscle pump, respiratory pump, sympathetic stimulation(vasoconstriction) increases venous return
Describe the factors that determine the resistance to flow. Which factor is more important physiologically?
3 Major Factors: 1) blood viscosity(n) - determined by hematocrit(fraction of total blood volume occupied by the formed elements such as RBC 2)total blood vessel length(L) - increase the total amount of friction 3) Blood vessel radius - when raids is small there is more surface friction - CAUSES THE MOST CHANGE
Differentiate active hyperemia from reactive hyperemia. Describe the chemical factors that contribute to both kinds of local control.
ACTIVE HYPEREMIA: increase metabolic activity causes start REACTIE HYPERIMA: blood supply to the organ is blocked ** both result in production of same local signals that problem vasodilatation(blood flow)
· Describe the physical factors that influence pulmonary ventilation. o Airway resistance o Alveolar surface tension o Lung compliance
Airway resistance: primary determinate of resistance to airflow is radius of airways - decrease radius, increase airflow, increase work of breathing Lung compliance
Define arteries, veins, and capillaries.
Arteries: carry blood away from heart Veins: carry blood towards heart Capillaries: small vessels that connect the two
Draw an oxygen-hemoglobin dissociation curve. Explain the significance of the flat region of the curve at higher PO2, and of the steep region at lower PO2.
As PO2 increases, the percent of hemoglobin saturated with O2 increases until all of the O2 -binding sites are occupied (100% saturation). At normal PaO2 of 100 mmHg, Hb is 98% (nearly 100%) saturated . Systemic venous blood has PO2 of 40 mmHg, and is typically 75% saturated with O2.
· Describe how temperature and 2,3-BPG affect oxygen binding to hemoglobin.
BPG = 2,3-bisphosphoglycerate; an intermediate product of anaerobic glycolysis by RBCs. BPG binds reversibly with Hb to lower Hb affinity for O2 TEMP; Increasing temp weakens Hb affinity to O2, cause the right shift of the curve. Advantage: enhance O2 unloading in active tissues.
· Describe the neuronal, endocrine, and paracrine factors that affect airway radius and thus influence airway resistance.
Bronchoconstirction: - neural control: parasympathetic simulation -chemical control: histamine and other inflammatory chemicals -edema of the walls -excess mucus Brnconchodialtion: - neural control: sympathetic stimulation -hormonal control: epinephrine
· Distinguish between conducting zone and respiratory zone. State the functions of the conducting zone of the airways.
CONDUCTING ZONE: -passages for air, no gas extange -anatomic dead space RESPIRTATORY ZONE: -respiratory bronchioles down to and including alveolar sacs -gas exchange happens at alveoli
· Describe the location and structure of the pleura. Relate the structure with the functions of the pleura.
DEF: thin, double layered membrane surround lungs FUNCTION: allow optimal expansion and contraction of the lungs during breathing
Define diffusion. Explain how diffusion happens at the systemic capillary beds. State the function of diffusion.
DEFINITION: movement of substance down it concentration gradient FUNCTION: exchange O2, nutrients and metabolic end products
· Define bulk flow. Describe the Starling forces that determine the direction of bulk flow. State the function of bulk flow.
DEFINTION: Movement of H2O and solutes together due to a pressure gradient - occurs continuously across capillaries between plasma and ISF FUNCTION: -not important in exchange - important in distribution of ECF between plasma and ISF. fluid shifts between ISF+ plasma provide temporal machismo to keep blood volume relatively constant
· Define dead space. Describe the effect of the anatomic dead space on alveolar ventilation.
Dead space is the volume not taking part in gas exchange and, if increased, could affect alveolar ventilation if there is too low a delivered volume
Describe how atmospheric and alveolar air differ in composition, and explain these differences.
Different gaseous makeup in the atmospheric and alveolar air - The atmosphere is almost entirely N2 + O2 - The alveoli contain more CO2 and water vapor and less O2 These differences reflect the effect of - Humidification of air by conducting zone - Mixing of alveolar air with atmospheric air that occurs with each breath -gas exchanges in the lungs
Explain the role of sympathetic nervous system in regulation of cardiac output and total peripheral resistance, which in turn regulates systemic arterial blood pressure.
EFFECT ON TPR - most arteriolar SM receives sympathetic innervation -this simulation causes SM with alpha 1 receptors produce vascular constriction - sympathetic control of arteriolar SM is essential for regulation of MAP and effect on TPR EFFECT ON CO injection of norepinephrine, increase HR which increase CO and then MAP
· Explain how decrease of total alveolar surface and increase of diffusion distance across the respiratory membrane influence pulmonary gas exchange.
Emphysema - destruction of alveoli and consequent loss of surface area Surgical removal of lung (or lung lobe) would also reduce alveolar surface area
· Hormones that are involved in regulation of blood pressure. Explain the roles of the following hormones in the regulation of MAP. o Epinephrine and norepinephrine o Angiotensin II o Antidiuretic hormone (ADH) o Atrial natriuretic peptide (ANP)
Epinephrahr and noerphienphin(same as sympathetic)INCREASE BP: - increase CO - vasoconstriction Angiotensin II INCREASE: - vasoconstriction Antidiuretic hormone (ADH) INCREASE: -stimulates riders to keep H2O, increase Blood volume, -vasoconstrict Atrial natriuretic peptide (ANP)DECREASE: -stimulates kidneys, excrete Na+ and H2O, decrease blood volume -vasodiolation
Write the equation that describes the relationship between flow, pressure gradient, and resistance.
F(flow rate)=(change in pressure)/ Resistance
· Write the equation that describes the relationship between airflow rate, atmospheric pressure, alveolar pressure, and airway resistance.
F= change in presssure/R
Explain what determines blood flow to each individual organ.
Flow organ= MAP/ R organ
Explain why the diffusion of gas into or within liquids is determined by its partial pressure gradient rather than concentration gradient.
Gas molecules exist in gas mixtures and also in liquid. When gases dissolve in liquid they 'disappear' into solution (Bubbles of gas are not in solution) .Gases dissolved in liquid exert a partial pressure .The partial pressure of a gas dissolved in liquid equals to the partial pressure of the same gas in the gas phase with which the solution is at equilibrium.
Describe both the intrinsic (or local control) and extrinsic factors that regulate arteriolar radius and their corresponding functions.
INTRISTIC FACTORS: - metabolic or magnetic controls -distribute blood flow to individual organs and tissues as needed EXTRINSIC FACTORS:- neural or hormonal controls - Maintain MAP - redistribute blood during exercise and thermoregulation
· Describe the structure of the respiratory mucosa (pseudostratified ciliated columnar epithelium) that covers most parts of the airway. State the function of the mucociliary escalator.
If it stops working it could cause - chronic smokers cough( inhibits Hilary activity; coughing is only way smokers can clear mucus from trachea and bronchi) -Cystic fibrosis(genetic disorder)
Describe how oxygen is transported in blood and the relative amount transported in each form.
In a healthy person with [Hb] = 15 gm/dl and PaO2 = 100 mm Hg, approx 20 ml O2 are carried in each 100 ml of systemic arterial blood (20 ml O2/dl).This O2 is transported in two forms: A small amount (≈1.5% of total) of O2 is dissolved in plasma and this O2 is responsible for the blood PO2 (free gas). Vast majority (≈98.5 % of total) is reversibly bound to hemoglobin
· Describe the components of the respiratory membrane.
It is a thin membrane composed of an alveolar and capillary wall. The respiratory membrane is made up of thin squamous epithelium of alveoli, the endothelium of blood capillaries and the basement substance present between them
· Describe the major neuronal inputs to the respiratory control centers in the brain stem.
LOOK AT SLIDE
Explain the relationship between mean arterial pressure (MAP), cardiac output (CO), and total peripheral resistance (TPR). Write an equation to describe such relationship.
MAP= CO X TPR
Define mean arterial pressure (MAP) and write the equation for estimation of MAP. Explain the importance of a normal level of MAP.
MAP= DP+1/3( PP)
· Describe the respiratory control centers in the brain stem.
Medullary respiratory centers: - VRG: the primary generator of the respiratory rhythm. Contains inspiratory neurons and expiratory neurons. - DRG: integrates peripheral inputs from stretch & chemoreceptors and modifies the respiratory rhythm. Pontine respiratory centers: - Receives input from higher brain centers and issues output to both DRG and VRG .- modify the pattern established in the medulla, smooth out the transitions from inspiration to expiration.
· Differentiate between minute ventilation and alveolar ventilation.
Minute ventilation, is a measurement of the amount of air that enters the lungs per minute. It is the product of respiratory rate and tidal volume. Alveolar ventilation, takes physiological dead space into account
Explain the functional importance of negative pressure in the pleural cavity.
Negititive pressure acts as a suction to keep the lungs from collapsing
· Describe the structure and function of hemoglobin.
O2 binds to the Fe atom in the heme group of a hemoglobin molecule. -contains oxygen to deliver to rest of body
Explain the mechanism of pulmonary gas exchange.
O2 diffuses from alveoli to pulmonary blood CO2 diffuses from pulmonary blood to alveoli
· Describe how pH and PCO2 affect oxygen binding to hemoglobin (Bohr's effect).
PH: H+ ions weaken Hb affinity to O2, cause the right shift of the curve . Advantage: enhance O2 unloading in active tissues. PCO2 Bohr effect: declining blood pH or increasing PCO2 weakens Hb affinity to O2, causes the right shift of the curve. Advantage: enhance O2 unloading in tissues.
Describe the direction of blood flow in both pulmonary circulation and systemic circulation.
PULMONARY: arteries carry deoxygenated, veins carry oxygenated SYSTEMIC: arteries carry oxygenated, veins carry deoxygenated
· Describe how gas exchange happens between tissues and systemic capillary blood.
Partial pressure gradients reverse of those in pulmonary capillaries Process is essentially the same, opposite flows Even at PO2 of 40 mmHg, Hb is still 75% saturated, could release more O2 if tissue metabolic rate goes up.
Explain how long-term regulation of local blood flow is achieved.
Process called Angiogenesis: increase number of blood vessels in each region
· Explain the function and importance of pulmonary surfactant in increasing lung compliance.
Pulmonary surfactant thus greatly reduces surface tension, increasing compliance allowing the lung to inflate much more easily, thereby reducing the work of breathing. It reduces the pressure difference needed to allow the lung to inflate.
· Distinguish respiratory acidosis, respiratory alkalosis, metabolic acidosis, and metabolic alkalosis. Explain how the lungs can help to correct metabolic acid/base imbalances.
RESPITORY Respiratory acidosis - decreased pH due to decreased ventilation- Hypoventilation (slow, shallow breath increase CO2)- Impaired lung function (pneumonia, emphysema) Respiratory alkalosis - increased pH due to increased alveolar ventilation- Hyperventilation (due to stress or pain) METABOLIC All abnormalities of acid-base imbalance except those caused by too much or too little CO2 in the blood. Metabolic acidosis (Low blood pH and HCO3-)Typical causes: - Generate too much acid • Too much alcohol (alcohol is converted to acetic acid) • Accumulation of lactic acid during exercise • Diabetic crisis or starvation (acetoacetic acid) - Loss of HCO3-• Excessive loss of HCO3 - caused by persistent diarrhea• Kidney failure (fail to reabsorb HCO3-) Metabolic alkalosis (rising blood pH and HCO3- levels) - loss of H+ (vomiting) - Intake of excess base (e.g. antacids)
Explain the parallel arrangement in systemic circulation, which allows blood flow to individual organs to be adjusted independently.
Redistributed blood based on activity- simulated by chemoreceptors to change size
Describe blood pressure in different regions of the systemic circulation (e.g., aorta, arteries, arterioles, capillaries, venules, veins).
Systemic circulation: High pressure Pulmonary: low pressure Systolic pressure= contraction of ventricle Diastolic= relaxation of ventricle ** decreased elasticity of blood vessels with aging leads to increase SP**
State Henry's law.
The amount of gas molecules that can dissolve in an aqueous solution is proportional to its partial pressure gradients in the two phases and its solubility in the liquid
Describe the autonomic innervation of the lungs. Explain the effects of parasympathetic and sympathetic stimulation on the airways.
The parasympathetic system causes bronchoconstriction, whereas the sympathetic nervous system stimulates bronchodilation. Reflexes such as coughing, and the ability of the lungs to regulate oxygen and carbon dioxide levels, also result from this autonomic nervous system control.
State Dalton's law of partial pressure.
The total pressure in a gas mixture is the sum of partial pressures of each individual gas
· Describe the structure of the alveoli. Differentiate between type I alveolar cells and type II alveolar cells.
Type I alveolar cells are squamous extremely thin cells involved in the process of gas exchange between the alveoli and blood. Type II alveolar cells are involved in the secretion of surfactant proteins
· Explain how ventilation-perfusion coupling influences the efficiency of pulmonary gas exchange. Explain how ventilation-perfusion mismatch could be corrected by local autoregulatory mechanisms within the lungs.
Ventilation (V): the amount of gas reaching the alveoli Perfusion (Q): the amount of blood flow in pulmonary capillaries Appropriate matching of ventilation to perfusion in all lung regions is essential for efficient pulmonary gas exchange
· Describe the anatomy of capillary beds. Describe the wall of the capillaries.
Wall of cappilery is made single layer endothelial cells
Explain how inspiratory muscle contraction causes the expansion of the thoracic cavity and expansion of the lungs.
allows thoracic cavity to as a bellows to move air in and out - all skeletal muscles -under somatic nervous system
Explain why arterioles are the major sites of resistance in the systemic vascular system and why blood pressure drops significantly as blood flows through the arterioles.
cause they have the smallest diamameter
Long term BP mechanisms
contract changes in BP by altering Blood volume
Explain the relationship between flow, velocity, and cross-sectional area. Describe the relative velocity of blood flow in different regions of the systemic circulation.
exchange between blood and ISP at capillaries depends on low velocity of blood flow in capillaries
Explain the normal resting expiration and why it is considered as a passive process. Describe the muscles involved in active expiration.
expiration= passsive( diaphram relaxes, inspiratory muscles relax) During active expiration, the most important muscles are those of the abdominal wall (including the rectus abdominus, internal and external obliques, and transversus abdominus), which drive intra-abdominal pressure up when they contract, and thus push up the diaphragm, raising pleural pressure, which raises alveolar
· Explain the mechanisms that determine lymph flow.
flows toward heart - compression by surrounding tissues(skeletal muscle contraction) - one-way valves
Explain how alveolar surface tension is generated, how alveolar surface tension influences pulmonary ventilation. Describe what cell types produce surfactant and how surfactant helps to reduced alveolar surface tension.
fluid in an alveolus produces surface tension - surface tensions is reduced by a surfactant secreted by Type II alveolar cells
· Chemoreceptor reflex: Outline the chemoreceptor reflex initiated by a decrease in blood O2 or an increase in blood CO2.
location of Chemoreceptors: -Carotid - Aortic STIMULI - when O2 or pH drops, or CO@ levels rise- chemoreceptors are simulated, increase pulse to cardiovascular center, increase sympathetic output, increase BP ** not active until MAP drops below 60-80mmHg-most important in regulation of respiration
· Baroreceptor reflex (the most important mechanism): Explain the sequence of events in the baroreceptor reflex that occur after a sudden change in arterial blood pressure. Your explanation should include changes in baroreceptors, afferent nerve activity, CNS integration, efferent nerve activity to the SA node, AV node, ventricles, arterioles, and venules.
look at slides
· Write the equation for lung compliance as it relates to the magnitude of the change in lung volume with a given change in transpulmonary pressure. Describe the two determinants of lung compliance.
lung compliance = change in volume/ change DETERMINATES: 1) alveolar surface tension forces(=2/3) 2) tissue elastic forces= 1/3
· Define pneumothorax and atelectasis. Describe the major cause(s) of pneumothorax.
pneumothorax occurs when air leaks into the space between your lung and chest wall. This air pushes on the outside of your lung and makes it collapse.CAUSES: chest injury, lung seaside atelectasis can be a collapse of only a portion of the lung
Describe Boyle's law relating volume and pressure in a container of gas molecules. Relate Boyle's law to events of inspiration and expiration.
states that the pressure of a fixed number of molecules is realtinoed to the volume of a container in which they are placed -
Describe the anatomy of the respiratory system from the nose all the way down to the alveoli.
upper respiratory tract: -nose, mouth, pharynx, and larynx lower respiratory tract: -trachea, bronchi, bronchioles, alveoli
Explain how partial pressure gradients and gas solubility influence pulmonary gas exchange.
Δ PO2 −PO2 in alveolar gas is 104 mmHg −PO2 in the blood (at the start of the pulmonary capillary) is 40 mmHg −Δ PO2= 64 mmHg Δ PCO2 −PCO2 in alveolar gas is 40 mmHg −PCO2 in the blood (at the start of the pulmonary capillary) is 45 mmHg −Δ PCO2= 5 mmHg
