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Human Physiology > Unit 4 > Flashcards

Unit 4 Flashcards

1
Q

What are the six major functions of the respiratory system?

A
  1. Exchange of gases btwn the atmosphere and bloodstream: O2 is picked up from atmosphere and delivered to blood while CO2 is removed from blood and enters atmosphere.
  2. Regulation of pH
  3. Pathogen protection
  4. Vocalization
  5. Providing a route for water and heat loss
  6. Activation of some plasma proteins
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2
Q

What are the four integrated processes for external respiration?

A
  1. Pulmonary ventilation–exchange of air
  2. Gas exchange btwn lungs and bloodstream (simple diffusion)
  3. Gas transport
  4. Exchange btwn blood and tissues
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3
Q

The conducting zone (or tree), starting with where air travels from and to, consists of these six anatomical regions…

A

Air travels beginning to end:

  1. Nasal cavity
  2. Pharynx
  3. Larynx
  4. Trachea
  5. Bronchi
  6. Bronchioles
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4
Q

The respiratory zone (or gas exchange tissue) includes which anatomical structure?

A

Alveoli

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5
Q

What are two pulmonary problems in the respiratory zone and how does it affect alveoli?

A
  1. Emphysema: destroys alveoli → lack of oxygenation and buildup of CO2
  2. Pneumonia: accumulation of fluid btwn alveoli and blood vessel makes gas exchange harder
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6
Q

How are the lungs associated with the pleural cavities, visceral pleura, parietal pleura?

A

Fist in balloon :: Lung in pleural cavity

The inner part where lung touches pleural cavity is visceral pleura; the outer part where lung does NOT touch pleural cavity is parietal pleura.

When we breathe, the membranes of the pleural cavity and lungs rub against each other for gas exchange.

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7
Q

What are the five pulmonary pressures?

A
  1. Resting pressure: apnea (period of NOT breathing)
  2. Atmospheric pressure = 760 mm Hg
  3. Intra-alveolar (intrapulmonary pressure aka pressure in lungs) = 760 mm Hg that is set to 0 mm Hg
  4. Intrapleural pressure (aka pressure in pleural cavity) = 756 mm Hg or -4 mm Hg
  5. Transpulmonary or mural pressure = 4 mm Hg
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8
Q

What is pneumothorax?

A

An abnormal condition where air is in the pleural space that separates the lung from the chest wall.

Intrapleural pressure going -4 mm Hg to 0 mm Hg, so there’s nothing pulling lungs out b/c if pressure increases, volume decreases. PLUS, there’s still elasticity so, like a rubber band, lung will COLLAPSE.

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9
Q

What is the formula for flow?

A

F = ΔP/R

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10
Q

What is Boyle’s Law?

A

Pressure and volume are inversely related.

Pressure ↑, Volume ↓ (and vice versa)

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11
Q

Explain the seven steps for NORMAL RHYTHMIC INSPIRATION.

A

Step 1: An ACTIVE process b/c it involves contraction of diaphragm and external intercostal muscles.

Step 2: This muscle contraction causes the thoracic cavity to enlarge. And as thoracic cavity expands, the pleural cavity expands… Volume ↑

Step 3: Intraplueral pressure then DECREASES from -4 to -6 mm Hg (Boyle’s law)… Pressure ↓

Step 4: This expands the lungs to fill the empty space… Volume ↑

Step 5: The intra-alveolar pressure DECREASES from 0 to -1 mm Hg… Pressure ↓

Step 6: This allows the atmospheric pressure to push air into lungs

Step 7: The intra-alveolar pressure then INCREASES back to zero and air STOPS moving IN

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12
Q

Explain the seven steps for NORMAL RHYTHMIC EXPIRATION.

A

Step 1: A passive process b/c it causes the relaxation of the diaphragm and external intercostal muscles

Step 2: This causes the thoracic cavity to compress… Volume ↓

Step 3: The intrapleural pressure increases from -6 to -4 mm Hg… Pressure ↑

Step 4: This compresses the lungs… Volume ↓

Step 5: The intra-alveolar pressure increases from 0 to +1 mm Hg… Pressure ↑

Step 6: This forces the air in the lungs to move outward

Step 7: The intra-alveolar pressure then decreases back to zero and air STOPS moving OUT

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13
Q

Explain the seven steps for ENHANCED (FORCED) INSPIRATION.

A

This is an amplification of the normal pattern. It’s an ACTIVE process.

Step 1: Recruits more muscle fibers in diaphragm and external intercostal muscles and may involve accessory inspiratory muscles such as scalene muscles and sternocleidomastoid.

Step 2: Muscle contraction causes thoracic cavity to enlarge… Volume ↑

Step 3: Intrapleural pressure then DECREASES from -4 to -8 mm Hg… Pressure ↓

Step 4: This expands the lungs to fill empty space… Volume ↑

Step 5: Intra-alveolar pressure DECREASES from 0 to -2 mm Hg… Pressure ↓

Step 6: This allows the atmospheric pressure to push air into lungs.

Step 7: The intra-alveolar pressure then increases back to zero and air STOPS moving IN.

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14
Q

Explain the seven steps for ENHANCED (FORCED) EXPIRATION.

A

This is an amplification of the normal pattern, EXCEPT it’s an ACTIVE process.

Step 1: It involves the contraction of abdominal muscles and internal intercostal muscles and the relaxation of the respiratory muscles.

Step 2: This causes the thoracic cavity to compress.

Step 3: The intrapleural pressure increases from -8 to -2 mm Hg.

Step 4: This compresses the lungs.

Step 5: The intra-alveolar pressure increases from 0 to +2 mm Hg.

Step 6: This forces the air in the lungs to move outward.

Step 7: Intra-alveolar pressure then decreases back to zero and air STOPS moving OUT.

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15
Q

What are three factors affecting pulmonary ventilation?

A
  1. Lung compliance
  2. Surface tension
  3. Airway resistance
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16
Q

What is lung compliance?

A

A factor affecting pulmonary ventilation.

Higher compliance (ease of stretchability) aids ventilation (air gets in easier).

Emphysema INCREASES compliance

Fibrosis DECREASES compliance

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17
Q

What is surface tension?

A

A factor affecting pulmonary ventilation.

Hinders ventilation.

Surfactant: reduces surface tension by reducing water cohesion to allow stretchability of alveoli. Eases ventilation.

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18
Q

What is airway resistance?

A

Resistance is influenced by bronchiolar diameter and the amount of mucus. Bronchiolar constriction restricts ventilation.

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19
Q

What are the physical factors for airway resistance?

A

Inspiration: lungs expand, bronchioles expand

Expiration: lungs compress, bronchioles compress

Asthma: have bronchiolar constriction from smaller diameter and mucus buildup… inhale is easy, but exhale is hard b/c bronchioles compress TOO MUCH during expiration.

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20
Q

What are the nervous system controls for airway resistance and what receptors control them?

A

Sympathetic: bronchioles dilate (Beta2 receptors)

Parasympathetic: bronchioles constrict (muscarinic receptors)

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21
Q

What are the chemical controls for airway resistance?

A

Epinephrine: bronchioles dilate

Histamine: bronchioles constrict

Anti-histamine: bronchioles dilate

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22
Q

What is Chronic Obstructive Pulmonary Disease (COPD)?

A

Difficulty breathing.

Major prob: smoking

Two major causes:

  1. Emphysema: destruction of lung tissue, less elasticity and increased compliance, bronchioles tend to collapse (less air passage. prob w/ low O2 and too much CO2)
  2. Chronic bronchitis: inflammation and mucus production, chronic cough, constriction of bronchioles
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23
Q

What are two pulmonary function tests (tests to see how efficient you’re getting air in and out)?

A
  1. FEV1 : forced expiratory volume in one second
  2. Peak expiratory flow (PEF): measures max volume of air breathed out
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24
Q

What is tidal volume?

A

Amount of air being displaced between normal inspiration and expiration.

Tidal volume = 500 mL

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25
Q

What is anatomical dead space?

A

The volume of air in conducting portion.

Anatomical dead space = 150 mL

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26
Q

What is total ventilation or minute ventilation?

A

Kinda like cardiac output…

Total ventilation = Respiration frequency (# of breaths w/in a set amt of time) x Tidal volume

= 12 x 500

= 6000 mL/minute

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27
Q

What is alveolar ventilation?

A

Alveolar ventilation = Respiratory frequency x Fresh air in lungs

= Respiratory frequency x (Tidal volume - Anatomical dead air space)

= 12 x (500 - 150)

= 4200 mL/min

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28
Q

What are three controls for ventilation?

A
  1. Factors responsible for rhythmic ventilation
  2. Factors that regulate rate and depth of ventilation
  3. Factors that influence voluntary control
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29
Q

Explain the factors responsible for rhythmic ventilation.

A

Dorsal respiratory group contains rhythmic respiratory neurons (think of it like the SA node).

The rhythmic respiratory neurons fire inspiration neurons when we inhale, then it stops firing when we exhale. This is automatic, not voluntary.

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30
Q

Explain the factors that regulate rate and depth of ventilation.

A

2 kinds of chemoreceptors:

  • Peripheral chemoreceptors in arteries
  • Central chemoreceptors in medulla oblongata

What’s goin on during…

Hypoventilation (breathing slowly): CO2 ↑, O2 ↓, H+ ↑… leads to more ventilation.

Hyperventilation (breathing quickly): CO2 ↓, O2 ↑, H+ ↓… leads to less ventilation.

CO2 is most important stimulus!

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31
Q

Explain the factors that influence voluntary control for ventilation.

A

Cerebral cortex can override rhythmic breathing… but you can’t hold breath forever b/c CO2 buildup makes you breathe.

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32
Q

What is Dalton’s Law of Partial Pressure?

A

Partial pressure of a gas = (its percent of the total) x (atmospheric pressure).

One atmosphere at sea level is 760 mm Hg: 79% is nitrogen gas and 21% is oxygen gas.

… so the partial pressure of N2 is 600 mm Hg (760x0.79) and partial pressure of O2 is (760x0.21).

The higher you go up in altitude, the smaller the atmospheric pressure. Ex: at 18k feet, atmospheric pressure is 380 mm Hg… so PO2 is 80 mm Hg (380x0.21).

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33
Q

What is Henry’s Law?

A

How much gas dissolves into a liquid state is proportional to the gas’s partial pressure.

Factors that affect the how much gas dissolves into a liquid state:

  1. Temperature of liquid: the higher the temp, the less amount of dissolved gases
  2. Equilibrium w/ the partial pressure in the atmosphere (or lung alveoli): higher the partial pressure in the atmosphere (or alveoli), the higher the potential amount in the liquid (or bloodstream).
  3. Solubility differences: CO2 is 20x more soluble than O2 in water or blood… sooo even if they have equal partial pressures, CO2 has a greater concentration in the liquid.
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34
Q

What causes the dilution of PO2 = 160 from atmosphere to alveoli air of PO2 = 100?

A

The presence of carbon dioxide and water vapor in the lungs and the dilution by the low oxygen levels in the dead air space.

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35
Q

What are the five typical partial pressure values of O2 and CO2in atmospheric air and at various sites in the body?

A
  1. Atmospheric/inspired air: PO2 = 160; PCO2 = 0.3
  2. Alveolar pressure: PO2 = 100; PCO2 = 40
  3. Pulmonary veins and systemic arteries: PO2 = 100; PCO2 = 40
  4. Systemic veins and pulmonary arteries: PO2 = 40; PCO2 = 46
  5. Expired air: PO2 = 116; PCO2 = 32
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36
Q

At the pulmonary capillaries, which direction are O2 and CO2 going?

A

O2is going INTO pulmonary capillaries FROM alveoli.

CO2 is going OUT OF pulmonary capillaries INTO alveoli.

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37
Q

At the systemic capillaries, which direction are O2 and CO2 going?

A

O2 is going OUT OF systemic capillaries INTO cells in tissues throughout body.

CO2 is going INTO systemic capillaries FROM cells in tissues throughout body.

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38
Q

Describe two types of oxygen transport.

A

200 mL oxygen gas per liter of blood TOTAL.

  1. Dissolved oxygen (1.5%): 3 mL oxygen gas per liter of blood.
  2. Bound to hemoglobin (98.5%): 197 mL oxygen gas per liter of blood.

O2 + Hb ⇔ Hb - O2 (basically know more O2 shifts equation to right, so there’s a greater saturation on hemoglobin)

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39
Q

Describe the Oxygen-Hemoglobin Dissociation (Saturation) Curve and the two important areas of the graph’s sigmoid-shaped curve.

A

Higher PO2 in atmosphere (or alveoli) → more amount dissolved in blood → greater amount of O2 bound to hemoglobin

Two important areas in the graph:

  1. Plateau: hemoglobin maintains high O2 saturation when partial pressure of O2 drops from 100 mm Hg to 60 mm Hg.
  2. Reserve: 75% O2 reserve is available for exercising muscles with partial pressure of 40 mm Hg.
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40
Q

What factors influence Oxygen-Hemoglobin Curve?

A
  1. A shift DOWNWARD to the RIGHT will DECREASE affinity of O2 to hemoglobin, making it easier to unload O2 from hemoglobin molecule. [RIGHT: right; increase in BPG, hydrogen ions, and temperature] Occurs in skeletal muscle capillaries during exercise.
  2. A shift UPWARD to the LEFT will INCREASE affinity of O2 to hemoglobin, making it easier to attach O2 to hemoglobin. [Decrease in BPG, hydrogen ions, and temperature] Occurs in pulmonary capillaries
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41
Q

What is Hemoglobin F?

A

Fetal hemoglobin has a higher affinity to O2 than maternal hemoglobin because it cannot bind to BPG (BPG lowers affinity to oxygen).

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42
Q

Describe three types of carbon dioxide transport.

A
  1. Dissolved CO2 (directly into blood)
  2. Carbamino hemoglobin (binding of CO2 to hemoglobin. This is reversible, so when it reaches lungs, CO2 and Hb can split and CO2 can be expelled from body)
  3. **Bicarbonate** (Allows for continued uptake of CO2 into blood. This makes more H+. This is important b/c when partial pressure of O2 and CO2 change at high altitudes, the bicarbonate buffer system adjusts to regulate CO2 while maintaining correct pH in the body.
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43
Q

What are the seven functions of the urinary system?

A
  1. Regulation of plasma ion concentration. Electrolytes are Na+, Cl-, K+, bicarbonate, Ca2+, Mg2+, and phosphates.
  2. Regulation of plasma osmolarity
  3. Regulating plasma volume and blood pressure
  4. Regulation of plasma hydrogen ion concentration, Homeostasis of acid-base
  5. Elimination of waste such as urea, uric acid, and ketones, etc.
  6. Excretion of foreign materials (drugs, etc.)
  7. Hormon production (erythropoietin, renin, Vitamin D3)
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44
Q

What are kidneys?

A

The functional organs within the system that carry out the seven urinary system functions.

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45
Q

What are the ureters?

A

Muscular conducting tubes that transport urine from the kidney to the bladder.

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46
Q

What is the urinary bladder?

A

An organ that stores urine and has smooth muscle in its wall.

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47
Q

What is the urethra?

A

A transport tube form the bladder to the outside environment.

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48
Q

What three areas is the kidney composed of?

A
  1. Outer renal cortex: fluid leaves the blood in the cortex
  2. Middle renal medulla: fluid is modified by the cortex and medulla
  3. Inner renal pelvis: fluid is excreted as urine from cortex through medulla into pelvis and out of ureter.
49
Q

What are nephrons and what are its four components?

A

Functional units in the kidneys.

There are 1.25 million nephrons/kidney

Components:

  1. Bowman’s capsule
  2. Proximal convoluted tubule (touches Bowman’s capsule)
  3. Loop of Henle
  4. Distal convoluted tubule (touches collecting duct)
50
Q

Describe the direction of blood flow.

A

At rest, blood flow through the kidney is about 20% of the total cardiac output.

Various arteries → Afferent Arteriole → Glomerulus (capillary bed) → Efferent arteriole → Peritubular capillaries → Veins

51
Q

What are the three basic renal exchange processes?

A
  1. Filtration
  2. Reabsorption
  3. Secretion
52
Q

Explain the FILTRATION process during renal exchange.

A

Fluid from the bloodstream leaves the glomerulus and enters the lumen.

53
Q

What three factors influence filtration = GFR (glomerular filtration rate)?

A
  1. Myogenic or auto-rhythmic control over afferent artiole diameter.

Blood pressure and GFR are directly related until GFR becomes constant because as blood pressure increases, afferent arterioles will eventually vasoconstrict and leave GFR constant.

  1. Nerves: (remember, no dual innervation. just sympathetic)

Sympathetic stimulation to AFFERENT arteriole: vasoconstriction will DECREASE GFR (less blood, less pressure, less filtration).

Sympathetic stimulation to EFFERENT arteriole: vasoconstriction will INCREASE GFR.

  1. Osmotic pressure:

As COP increases, GFR decreases.

54
Q

Explain the REABSORPTION process during renal exchange.

A

Most of the components of the filtrate are not excreted as urine but are reabsorbed back into the peritubular capillaries.

Reabsorption is the movement of molecules and ions from the lumen of the nephron into the bloodstream of the peritubular capillaries.

99% is reabsorbed (other 1% is excreted):

  • 70% is reabsorbed in the PCT. This is important for reabsorption of sodium, water, urea, glucose, and chloride ions.
  • 20% is reabsorbed in loop of Henle. Critical in producing a salt concentration gradient in the kidney and in varying the urine concentration.
  • 9% is reabsorbed in the DCT and collecting duct. Influenced by hormones.

Reabsorption moves across two barriers: the tubular epithelium and the capillary endothelium.

Reabsorption may be active or passive. Active transport uses ATP or gradient energy and a carrier protein on one of the four membranes the chemical has to be transported across.

55
Q

What are the values for amount filtered, amount reabsorbed, and amount excreted for WATER?

A

For water:

Amount filtered: 180 L/day

Amount reabsorbed: 178.5 L/day

Amount excreted: 1.5 L

56
Q

What are the percent reabsorbed values for water, sodium, glucose, urea, and protein?

A

Percent reabsorbed:

Water: 99%

Sodium: 99.5%

Glucose: 100%

Urea: 50%

Protein: 100%

57
Q

Describe glucose and amino acid reabsorption.

A

Glucose and amino acids are 100% reabsorbed in the PCT where they use co-transport carriers with sodium ions.

Transport maximum:

  • Normal glucose in blood = 70-110 mg%. The amount of glucose filtered is below the transport max, thus all the glucose is reabsorbed.
  • Diabetic may have high blood glucose level of 500 mg%. Amount of glucose filtered is above the transport max, thus the excess amount of glucose is excreted. Dehydration occurs b/c water follows glucose.
58
Q

Describe sodium reabsorption.

A

Active transport of sodium occurs in the PCT, the ascending loop of Henle, DCT, and collecting duct.

Sodium reabsorption is influenced by aldosterone (which is produced by adrenal cortex that regulates sodium levels) in the DCT and collecting duct.

59
Q

Describe water reabsorption.

A

Passive reabsorption follows sodium by osmotic difference. For every sodium reabsorbed, water molecule is also absorbed in a permeable membrane.

Antidiuretic hormone (ADH), aka vasopressin, influences water reabsorption in the DCT and the collecting duct. This reduces urine.

Caffeine and alcohol inhibit ADH.

60
Q

Describe urea reabsorption.

A

Follows the osmotic gradient created by water reabsorption. 50% reabsorbed.

61
Q

Describe the SECRETION process during renal exchange.

A

Some substances enter the renal tubules by secretion from the peritubular capillaries into the tubular lumen. This can involve either active or passive transport mechanisms.

Hydrogen ions, potassium ions, and penicillin are secreted in this manner.

62
Q

Describe the EXCRETION process of renal exchange.

A

Excretion = amount filtered - amount reabsorbed + amount secreted = urine

63
Q

Describe micturition.

A

The urinary bladder (a storing organ) has a volume capacity between 600-800 mL. The wall contains smooth muscle (detrusor muscle) that is innervated by autonomic nerves. At the base of the bladder is the internal urethral sphincter of smooth muscle.

The detrusor muscle is relaxed, and the internal urethral sphincter is closed when the bladder is filling with urine.

Around the urethra is a band of skeletal muscle called the external urethral sphincter. This sphincter is closed when the muscle is contracted.

64
Q

Describe the basic spinal reflex for micturition.

A

300 mL of urine in the bladder cause stretch receptors to fire sending impulses to the spinal cord.

The efferent neurons stimulate parasympathetic nerves to contract the urinary bladder muscle.

Sympathetic inhibition opens the internal urethral sphincter while somatic inhibition relaxes and opens the external urethral sphincter. Urine will now flow from the bladder.

Tha brain stem and cerebral cortex can override the spinal reflex by inducing, voiding, or postponing it.

65
Q

What are the two functions of water homeostasis?

A
  1. Maintains the normal osmolarity at 300 milliosmole
  2. It maintains an adequate blood pressure and volume for oxygenation of tissues
66
Q

Describe water homeostasis.

A

60% of the body is water.

Water gain = Water loss.

Gain: food and drink (2.1 L) and metabolic water (0.3 L). Receptors for thirst

Loss: skin (0.35 L), lungs (0.35 L), feces (0.2 L), and urine (1.5 L).

67
Q

Describe osmotic gradient.

A

Role of the medullary osmotic gradient in water reabsorption.

Normal blood plasma concentration = 300 milliosomole = ios-osmotic urine.

Urine concentration varies w/ different physiological conditions.

Dilute urine is hypo-osmotic 100 milliosmole.

Concentrated urine is hyperosmotic 1200-1400 milliosmole.

A vertical osmotic gradient occurs in the kidney.

Concentrated medulla: Cortex is 300 milliosmole while the medulla will reach 1400 milliosmole

Special properties of the ascending loop include the active pumping of salts and its impermeability to water.

68
Q

What are the effects of ADH on the reabsorption in the collecting duct?

A

The collecting duct travels through the vertical salt gradient as it descends from the cortex to the medulla.

If no ADH is present: dilute urine is formed

If ADH is present: concentrated urine is formed (more ADH allows for more permeability within collecting duct)

ADH promotes production of water channel protein aquaporin.

69
Q

What are three types of water homeostasis reflexes?

A

Regulation of ADH production:

(1) Change in blood pressure
(2) Osmotic concentration
(3) Regulation of water filtration – GFR:
(3) Change in blood pressure

70
Q

Describe the two reflexes for regulation of ADH production.

A

1. Blood pressure:

↓ body water volume.

↓ blood pressure

↓ baroreceptor firing to hypothalamus

↑ ADH production and release from the hypothalamus/posterior pituitary

↑ water reabsorption in the distal convoluted tubule and collecting duct

↓ water excretion

↑ water retention

2. Osmotic concentration:

↓ body water volume

↑ in osmotic concentration

Stimulates osmoreceptors

↑ ADH production and release from the hypothalamus/posterior pituitary

↑ water reabsorption in the distal convoluted tubule and collecting duct

↓ water excretion

↑ water retention

71
Q

Describe the reflex for regulation of water filtration – GFR.

A

The baroreceptor reflex influences water filtration.

↓ body water volume

↓ plasma volume and blood pressure

↓ baroreceptor firing to medulla

↑ sympathetic activity to afferent arteriole

Vasoconstriction

↓ GFR

↓ water excretion

↑ water retention

72
Q

What are two ways to achieve sodium homeostasis?

A
  1. Sodium reabsorption by aldosterone
  2. Sodium regulation by atrial natriuretic peptide (ANP)
73
Q

What are the ten steps for sodium reabsorption by Aldosterone?

A

↑ reabsorption of sodium due to Aldosterone. This ↑ sodium transport in the DCT.

  1. ↓ sodium levels cause ↓ ECF volume.
  2. ↓ blood pressure.
  3. ↓ baroreceptor firing to the medulla oblongata.
  4. ↑ sympathetic stimulation to the macula densa of juxtaglomerular apparatus that causes the secretion of Renin.
  5. Renin activates Angiotensin, found in the blood, into Angiotensin I.
  6. Angiotensin I travels through the blood and is modified by the endothelial enzyme Angiotensin Converting Enzyme (ACE) into Angiotensin II.
  7. Angiotensin II activates the release of Aldosterone from the adrenal cortex.
  8. Aldosterone moves to the distal convoluted tubules and ↑ sodium reabsorption.
  9. ↓ sodium excretion.
  10. ↑ sodium retention.
74
Q

What are the four functions of Angiotensin II?

A
  1. Activates Aldosterone
  2. Vasoconstriction (of blood vessels to increase BP)
  3. Increases thirst and salt ingestion
  4. Increase ADH production and water reabsorption
75
Q

What are the eight steps for sodium regulation by atrial natriuretic peptide (ANP)?

A

Atrial natriuretic peptide (ANP) lowers sodium level in body when it is elevated.

  1. High sodium levels increases plasma volume (b/c more Na means more H2O) that stretches the atrial wall and activates ANP.
  2. ANP dilates the afferent arteriole and constricts the efferent arteriole both increase glomerular pressure and increases GFR.
  3. ↑ the filtration of sodium.
  4. ↑ sodium excretion.
  5. ANP also decreases Renin production.
  6. ↓ Aldosterone levels.
  7. ↓ sodium reabsorption.
  8. ↑ sodium excretion.
76
Q

Describe potassium homeostasis.

A

Potassium levels in the body are regulated through secretion.

An increase in potassium in the ECF increases ICF potassium. This higher potassium levels is secreted from the tubular cells.

An increase in potassium also stimulates Aldosterone release from the kidney to increase potassium secretion.

77
Q

Acid-base balance in the body is stabilized by what three factors?

A
  1. First by buffers: distributing H+
  2. Checked by respiratory compensation: if H+ too high, breathe less; if H+ too low, breathe more.
  3. Ultimately controlled by renal compensation in kidneys
78
Q

What are the four functions of acid-base balance?

A
  1. Maintain functional proteins
  2. Proper excitability of nervous system
  3. Maintain proper potassium ion levels
  4. Proper cardiac excitability and vascular diameter
79
Q

Explain the four things you can do in kidneys for renal compensation.

A
  1. Hydrogen ion secretion: secreted w/ or w/o sodium ions.
  2. Bicarbonate reabsorption: more bicarbonate, more buffer.
    - Secreted or filtered hydrogen ions attach to bicarbonate for carbonic acid
    - Carbonic acid is split by carbonic anhydrase to water and carbon dioxide
    - Water and carbon dioxide move into the tubular cell where they are re-synthesized into carbonic acid
    - Carbonic acid is split into bicarbonate and hydrogen ions
    - Bicarbonate is reabsorbed into the peritubular capillaries
  3. Formation of phosphates: secreted or filtered hydrogen ions attach to mono-hydrogen phosphate and forms dihydrogen phosphate that is excreted.
  4. Formation of ammonium
    - Amino acid glutamate is deaminated into ammonia
    - Ammonia binds to a hydrogen ion to form ammonium
    - Ammonium is secreted and excreted
80
Q

What is respiratory acidosis?

A

Respiratory depression or hypoventilation produces a buildup of carbon dioxide or hypercapnia.

Causes:

  • Depression in respiratory centers in brainstem (pons and medulla) caused by traume or over-sedation.
  • Asthma
  • Pneumonia
  • Pulmonary edema
  • Emphysema
81
Q

What is metabolic acidosis?

A

Causes:

  • Increase in acid production: ketoacidosis from diabeteres or a high protein or fat diet
  • Decrease in bicarbonate levels (less buffers, so more acidity): diarrhea, renal failure
82
Q

What is respiratory alkalosis?

A

Respiratory hyperventilation: creates a lack of carbon dioxide or hypocapnia

Causes:

  • Pulmonary diseases
  • High altitudes (less oxygen requires you breathe more)
  • Anxiety
83
Q

What is metabolic alkalosis?

A

Causes:

  • Buildup of bicarbonate or a loss of hydrogen ions frmo the body
  • Prolonged vomiting and lost of gastric acids (and hydrogen ions)
  • Excessive bicarbonate intake
84
Q

Respiratory compensation can be used for…

A

Metabolic acidosis: hyperventilation to lower carbon dioxide levels

Metabolic alkalosis: hypoventilation to raise carbon dioxide levels

85
Q

Renal compensation can be used for…

A

Both types of acidosis:

  • Increase hydrogen ion secretion
  • Increase in formation and excretion of phosphates and ammonium (b/c it gets rid of hydrogen ions)
  • Increase in bicarbonate reabsorption that can be used as a buffer in the bloodstream

Both types of alkalosis:

  • Decrease hydrogen ion secretion
  • Decrease in formation and excretion of phosohates and ammonium
  • Decrease in bicarbonate reabsorption and increase its excretion
86
Q

Describe the changes in plasma CO2, bicarbonate, and pH with acid-base disturbances.

A

Respiratory acidosis: ↓ pH, ↑ CO2, normal HCO3-

Metabolic acidosis: ↓ pH, normal CO2, ↓ HCO3-

Respiratory alkalosis: ↑ pH, ↓ CO2, normal HCO3-

Metabolic alkalosis: ↑ pH, normal CO2, ↑ HCO3-

87
Q

What event in the heart produces the systolic pressure in the arteries?

A

The arterial blood pressure has a high systolic pressure that is caused by the contraction of the ventricles.

88
Q

What feature of the large arteries maintains the diastolic pressure even though the pressure in the left ventricle plummets to just above 0 mmHg?

A

Elastic recoiling of the arterial walls on the blood during ventricular relaxation.

89
Q

What aspect of blood flow produces the thumping sound when listening and measuring a person’s blood pressure?

A

What aspect of blood flow produces the thumping sound when listening and measuring a person’s blood pressure?

What produes the thumping sound is the blood pulsating through the cuff w/ each heart contraction (systolic pressure). Diastolic pressure is when the sound disappears. This occurs b/c movement of blood changes from a pulsating flow to a quieter continuous flow.

90
Q

How would stimulation of the sympathetic nervous system containing alpha1 receptors on the arteriolar muscle change the amount of blood flow through the capillaries?

A

It would cause vasoconstriction of the arterioles producing less blood flow through the capillaries.

91
Q

What causes the skin to blanch?

A

Scrape causes vessel under skin to vasoconstrict which decreases blood flow and makes skin blanch.

92
Q

What causes the skin to flush red or darker?

A

Blood flow increases again when vessel vasodilates and turns skin red.

93
Q

Describe the triple response of inflammation and the mechanisms that produce each response.

A
  1. Red reaction at point of stimulation from vasodilation
  2. Spreading flare from red area fromchemical mediators stimulating local free nerve endings
  3. Wheal or raised area over red reaction from increase in vessel permeability and the movement of water from vessels to surrounding tissues
94
Q

What is the response of histamine to the skin and how does it change the diameter of the arterioles?

A

Turns red; vasodilates.

95
Q

What is the response of epinephrine to the skin and how does it change the diameter of the arterioles?

A

Turns white; vasoconstricts

96
Q

What is the purpose of using epinephrine with lidocaine before cutting into patient’s skin?

A

Reduce blood flow and loss by vasoconstriction of arterioles.

97
Q

Which chemical is responsible for the red and swollen response of your skin after a bug bite or sting?

A

Histamine

98
Q

What color does your finger turn when placed in warm water and what causes it?

A

Red; increase in blood flow caused by an elevated metabolic heart rate.

99
Q

How would blood flow change in skeletal muscles during exercise?

A

Blood flow increases.

100
Q

What happens to oxygen level in finger distal to rubber band?

A

Oxygen level decreases

101
Q

What color does your finger tuyrn after rubber band is removed and how does this change in blood flow relate to reactive hyperemia?

A

Very red.

Change in blood flow occurs in finger as blood quickly flows to distal end where there’s a lack of oxygen. Blood flow brings oxygen to distal end of finger.

102
Q

What is active hyperemia?

A

Increase in blood flow caused by an elevated metabolic rate.

103
Q

What is reactive hyperemia?

A

Increase in blood flow to the tissues when they have been deprived in oxygen.

104
Q

What effect does exercise have on the compression of veins in the feet?

A

Exercise helps increase blood flow in veins.

105
Q

How does exercise influence venous return?

A

It increases venous return.

106
Q

What is the function of valves in veins?

A

Enhance blood flow to the heart by lowering gravitational force on blood while standing and by preventing the back flow of blood into capillaries.

107
Q

What would happen to blood flow if there were failure in venous valves as seen with varivose veins?

A

You would have backflow and pool at the veins.

108
Q

What is hematocrit?

A

Represents the percentage of formed elements in blood or packed cell volume.

109
Q

Why would hematocrit value be low in anemics?

A

Anemics have low concentration of RBC or hemoglobin in bloodstream. So an anemic would have low hematocrit vale b/c hematocrit represents formed elements containing RBC.

110
Q

What might cause the percentages of blood types to change in the US over a long period of time?

A

Different people w/ different blood types breeding.

111
Q

What prevents one blood type from being used for a transfusion w/ an incompatible blood type?

A

Incompatability arises w/ blood transfusions when the antigen fmor the donot reacts w/ the antibody of the recipient.

112
Q

What blood type can be used as a universal donor? Include the Rh factor.

A

O negative

113
Q

What type of protein is lacking on a blood cell’s membrane that enables the blood to be used as a universal donor?

A

Lacks Rh antigen and AB antigen

114
Q

Could a Type A parent and a Type B parent produce children of Type O blood?

A

Yes. Type A could have gentyope AO, Type B could have genotype BO, so offspring can have genotype OO.

115
Q

Explain the reason a man w/ Rh-positive blood might be the father of an Rh-negative blood child?

A

Rh+ father could have genotype +-. His heterozygous gene makes it possible for the child to be Rh-.

116
Q

What is the clinical importance of examining the levels of creatinine in blood?

A

The kidneys maintain the blood creatinine in a normal range. Creatinine has been found to be a fairly reliable indicator of kidney function. If it’s too high, it could mean impaired kidney function.

117
Q

What is the clinical importance of examining the levels of aspartate aminotransferase in blood?

A

AST in the blood is directly related to the extent of the tissue damage. Low levels are normal, but when body tissue or an organ such as the heart or liver is diseased or damaged, additional AST is releated into bloodstream.

118
Q

What is the clinical importance of examining the number of neutrophils in blood?

A

Neutrophils fight infection. Too low levels increases risk of infection. Too high levels indicates premature release of myeloid cells from bone marrow.

Human Physiology (5 decks)

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