Univ IV Review Flashcards
List the five basic functions of the respiratory system
- Surface area for gas exchange
- Move air to and from the gas exchange area
- Protect respiratory system
- Producing sounds
- Detect odors
What structures make up the upper respiratory system
Nose, nasal cavity, paranasal sinuses, and pharynx
What structures make up the lower respiratory system
Larynx, trachea, bronchi, bronchioles, and alveoli
What are alveoli
Air-filled pockets where gas exchange takes place
What is the function of the paranasal sinuses
Produce mucus to protect nasal cavity
What is the main function of the nasal mucosa
Prepare air for arrival at the lower respiratory system
What is the main function of the larynx
Protect the glottis
What is the glottis
The vocal folds and the space between them
What is the role of the epiglottis
Prevents liquids and solids from entering the respiratory tract
What are type I pneumocytes
Squamous epithelial cells. The site of gas exchange.
What are type II pneumocytes
Produce surfactant
What is the function of alveolar macrophages
Phagocytize any invading particles
What is external respiration
All the processes involved in gas exchange between the body and the external environment
What is internal respiration
Absorption of O2 and release of CO2 by bodily cells
What is cellular respiration
The biochemical pathways responsible for O2 absorption and generation of CO2 by mitochondria
What is pulmonary ventilation
Breathing - moving air in and out of the lungs
What are hypoxia and anoxia
Hypoxia - low tissue O2 levels
Anoxia - O2 supply cut off completely
What is atmospheric pressure at sea level
760 mm Hg
What does Boyle’s Law state
The pressure of a gas is inversely proportionate to its volume
What is compliance of the lungs
How easily the lungs expand. Higher compliance = inflate easier
What factors affect the compliance of the lungs
Connective tissue, surfactant production, mobility of thoracic cage
What is the intrapulmonary pressure during inhalation in quiet breathing
759 mm Hg
What is a respiratory cycle
A single inhalation and exhalation
What is tidal volume
The amount of air you move in and out of your lungs during a normal respiratory cycle (quiet breathing)
What is pneumothorax
Air entering the pleural cavity
What is atelectasis
Recoiling of the elastic fibers of the lungs, aka “collapsed lung”
Which two muscles are primarily used during quiet breathing
Diaphragm and external intercostals
List all of the accessory muscles that are used in inhalation
- Sternocleidomastoid
- Scalenes
- Pectoralis minor
- Serratus anterior
List all of the accessory muscles that are used in exhalation
- Rectus abdominis
- Internal intercostals
- Abdominal obliques
- Transversus abdominis
- Transversus thoracis
What is a normal respiratory rate
12 to 18 breaths per minute
What is respiratory minute volume and how is it calculated
Amount of air moved each minute = [Respiratory Rate] x [Tidal Volume]
What is alveolar ventilation and how is it calculated
Amount of air reaching the alveoli per minute = [Respiratory Rate] x [Tidal Volume - Anatomic Dead Space]
What is the composition of ambient air at sea level
- 78.6% N2
- 20.9% O2
- 0.5% H2O
- 0.04% CO2
What is the partial pressure of a gas
The pressure contributed by a single gas in a mixture of gasses
How do you calculate the partial pressure of O2 at sea level
760 x 0.209 (= 158.84 mm Hg)
What does Henry’s Law state
At a given temperature, the amount of a particular gas in solution is directly proportional to the partial pressure of that gas
Note: This is what causes O2 to enter the blood at the lungs, and so on
Does alveolar air contain more or less CO2 than atmospheric air, and why?
Incoming air mixes with air remaining in the alveoli from the previous respiratory cycle. For this reason, alveolar air contains more CO2 (and less O2) than atmospheric air.
Why is the PO2 of exhaled air higher than the PO2 of alveolar air
Alveolar air mixed with air in the anatomical dead space as it is exhaled
Explain how the autonomic nervous system works with the respiratory system to dilate and constrict blood vessels and bronchioles
PO2 increase and CO2 decrease in the alveoli = vasodilation and bronchoconstriction
PO2 decrease and CO2 increase in the alveoli = vasoconstriction and bronchodilation
What are the two ways by which oxygen is transported in the blood
- 5% bound to hemoglobin (Hb)
1. 5% dissolved in plasma
What is hemoglobin saturation
The percentage of heme units containing bound oxygen at any given moment
How does the PO2 of plasma affect hemoglobin saturation
Hemoglobin carries and releases O2 in response to changes in the partial pressure of oxygen. As PO2 increases, Hb binds to O2. As pressure decreases, it releases oxygen.
Why does hyperventilating increase the saturation of hemoglobin from 97.5% to 100%
Hyperventilation –> Alkalosis –> Curve shifts left and up
What is the relationship between hemoglobin saturation and pH
Higher pH shifts curve to the left, increases saturation
How is hemoglobin saturation affected by temperature
Colder temperatures shift the curve to the left, increase saturation.
How does BPG affect oxygen release from hemoglobin molecules
More BPG shifts the saturation curve to the RIGHT, decreases saturation.
How is fetal hemoglobin different from adult hemoglobin
Fetal Hb binds to oxygen more readily, shifts curve to the left.
How is CO2 transported in the blood
- 70% transported as HCO3-
- 23% bound to Hb (carbaminohemoglobin)
- 7% dissolved in plasma
What is the chloride shift
HCO3- moving out of RBCs and Cl- moving into RBCs via countertransport. Requires no ATP.
What is hemoglobin attached to CO2 called
Carbaminohemoglobin
What happens to the interstitial PO2 and PCO2 when peripheral tissues become more active
Interstitial PO2 falls and PCO2 rises
How is oxygen and carbon dioxide transport and removal affected at active peripheral tissues
More oxygen is delivered and more carbon dioxide is carried away
What are the two components of the respiratory rhythmicity centers of the medulla oblongata
Dorsal Respiratory Group (DRG) and Ventral Respiratory Group (VRG)
(Chapter 24)
What structures make up the digestive system
Oral cavity, pharynx, esophagus, stomach, small intestine, large intestine
List the six integrated steps of the digestive system
- Ingestion
- Mechanical processing
- Digestion
- Secretion
- Absorption
- Excretion
What are mesenteries
Connects the parietal peritoneum to the visceral peritoneum
What is segmentation
The small intestine and some portions of the large intestine undergo cycles of contraction that churn and fragment the bolus, mixing the contents with intestinal secretions
List the three pairs of salivary glands and describe their secretions
Parotid: Large amounts of salivary amylase (breaks down carbohydrates)
Sublingual: Buffer and lubricate
Submandibular: Mixture of buffers, glycoproteins called mucins, and salivary amylase
What are the important functions of saliva
- Lubricate the mouth
- Lubricate food in the mouth
- Dissolve
- Contains salivary amylase and lingual lipase to begin digestion
What is the role of the mucus that covers the interior surface of the stomach
An alkaline mucous layer that protects epithelial cells against the acid and enzymes in the gastric lumen
What important products are secreted by the parietal cells of the gastric glands
HCl and Intrinsic factor (helps with absorption of B12)
How is HCl produced in the stomach
- Carbonic acid (H2CO3) is produced and dissociates into HCO3 and H+
- H+ is is transported into the lumen
- HCO3 is exchanged with Cl- ions from interstitial fluid
What is the alkaline tide
Parietal cells are excreting enough HCO3 (while making HCl) to raise the body’s pH significantly
What is the role of stomach acid (HCl)
- Kills most microorganisms ingested with food
- Denatures proteins and deactivates most enzymes in food
- Breaks down plant cell walls and connective tissues in meat
- Essential for activation and function of pepsin
What important compound is secreted by the chief cells of the gastric glands
Pepsinogen (which is then activated by HCl)
What are the functions of gastrin that is released by the pyloric glands
Gastrin stimulates secretion by both parietal and chief cells, as well as contractions of the gastric wall that mix and stir the gastric contents
What are gherkin, lepton, and obestatin
Gherkin - induces hunger
Lepton - induces satiety
Obestatin - thought to decrease hunger and thirst
Describe the three phases of gastric regulation
Cephalic phase: begins when you see, smell, taste, or think of food
Gastric phase: begins with the arrival of food in the stomach
Intestinal phase: begins when chyme first enters the small intestine
What stops the digestion of lipids and carbohydrates in the stomach
- Epithelial cells are covered by an alkaline mucous
- Lack of transport mechanisms
- Impermeable to water
- Digestion is not yet complete
What is the role of pepsin in the stomach
Digests protein
What is the function of the duodenal glands
Helps raise pH of chyme from 1-2 to 7-8
What are the three duodenal hormones
- CCK (cholecystokinin)
- Secretin
- GIP (gastric inhibitory polypeptide)
What is CCK
Cholecystokinin. Released when partially digested proteins and fat arrive at the duodenum.
- Stimulates gallbladder to release bile
- Inhibits gastric emptying
What is secretin
Released when acidic chyme arrives at the duodenum. Stimulates the release of HCO3- from the pancreas.
What is GIP
Gastric inhibitory polypeptide. Released when simple sugars arrive at the duodenum. Stimulates pancreas to release insulin.
How does the liver stabilize blood glucose levels
If glucose levels rise - synthesize glycogen and lipids
If glucose levels fall - breakdown glycogen and synthesize glucose
What percentage of cardiac output is received by the liver
25 percent
How are antibodies handled by the liver
The liver absorbs and breaks down antibodies, releasing amino acids for recycling
How are toxins addressed at the liver
Lipid-soluble toxins are stored in lipids, where they cannot damage cells
Other toxins are removed and broken down or excreted in bile
What are the components of bile
Bile consists mostly of water, with minor amounts of ions, bilirubin (a pigment derived from hemoglobin), cholesterol, and an assortment of lipids collectively known as bile salts
What is emulsification
Bile salts break fat into micelles
What is the primary function of the cecum
Begins the process of compaction
List the three vitamins that are produced by bacteria in the colon, and what are their functions
K - fat-soluble and required for synthesis of the four clotting factors
Biotin - water-soluble and important in various reactions, notably those of glucose metabolism
B5 - water-soluble and required in the manufacture of steroid hormones and some neurotransmitters
What are the three classes of digestive enzymes
Lipase, amylase, protease
What are the fat-solvable vitamins
A, D, E, K
What are the water-soluble vitamins
B and C vitamins
How is vitamin B12 absorbed
Bound to intrinsic factor
