Anatomy 2 Exam 3

Name the organs of the respiratory tract in order.

nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, alveoli

What do the organs in the conducting zone do?

filter, warm, and transport air

What do the organs in the respiratory zone do?

gas exchange

Describe the branching pattern of the airway.

trachea → primary bronchi → secondary bronchi → tertiary bronchi → bronchioles → alveolar sacs

Is the airway always open? What structures keep the airway open?

yes; rigid rings of cartilaginous tissue

Nasal Cavity histological features

pseudostratified ciliated columnar epithelium containing goblet cells produce mucus to trap debris; nasal conchae increase surface area for warming and humidifying air; olfactory epithelium acts as receptors for smell

Larynx histological features

stratified squamous epithelium in areas of high friction and respiratory epithelium elsewhere; contains cartilage that prevents food from entering the trachea during swallowing

Trachea histological features

C-shaped hyaline cartilage rings that keep the airway open; ciliated epithelial cells that propel mucus and trapped particles upward towards the pharynx

Bronchi histological features

cartilage that becomes more irregular as they branch and a layer of smooth muscle

Bronchioles histological features

prominent smooth muscle layer that can constrict or dilate to regulate airflow resistance; simple columnar/cuboidal epithelium which secrete surfactant-like material

Alveoli histological features

thin layer of squamous epithelial cells (type I alveolar) for fast diffusion, and type II alveolar cells that secrete surfactant to reduce surface tension and prevent collapse

Name the 3 components of the respiratory membrane

type 1 alveolar cells, basal lamina, capillary endothelial cells

What is the physiological significance of the 3 components of the respiratory membrane?

makes pulmonary gas exchange very efficient

Describe how the vocal folds contribute to speech

vibrating as air passes through them from the lungs creating a buzzing sound that is shaped into speech by the vocal tract

How does the nose protect the airway against dust particles and pathogens?

nose hairs and mucus trap large particles

How do the lungs protect the airway against dust particles and pathogens?

cilia and mucus move smaller debris upward for swallowing or coughing

How do alveoli protect the airway against dust particles and pathogens?

alveolar macrophages in the lungs engulf pathogens

How does the movement of the diaphragm drive ventilation?

contracting and flattening during inhalation to expand the thoracic cavity and relaxing during exhalation to force air out

Describe the inverse relationship of pressure and volume within the lungs

when thoracic volume increases, pressure decreases, and vice versa

What are the main muscles of inspiration?

diaphragm and external intercostals

Why aren’t there any main muscles of expiration?

when the diaphragm relaxes the air is pushed out

What does it mean to say that a particular muscle is an accessory muscle of inspiration or expiration?

muscles that assist the primary breathing muscles during increased demand, such as exercise, high exertion, or respiratory distress

Describe how the chest wall contributes to pulmonary ventilation

acts as the structural pump for ventilation

Describe how the pleural fluid contributes to pulmonary ventilation

lubrication

Describe how the elastic fibers around each alveolus contributes to pulmonary ventilation

give them the ability to return to their original shape after being stretched

Describe how surfactant contributes to pulmonary ventilation

reduces surface tension

Tidal Volume

the amount of air inhaled or exhaled during normal, quiet breathing

Inspiratory Reserve Volume

the additional, maximal amount of air that can be inhaled after a normal tidal inhalation

Expiratory Reserve Volume

the extra, forced amount of air that can be exhaled after a normal tidal expiration

Residual Volume

the volume of air remaining in the lungs after a maximal exhalation

What is vital capacity?

the maximum amount of air a person can exhale after a maximum inhalation

Oxygen and carbon dioxide both move across the capillary walls, from high to low ___.

pressure

Describe the 2 ways that oxygen travels in the blood.

dissolved in the plasma and bound to the heme of hemoglobin

Explain the significance of the oxygen-hemoglobin dissociation curve.

an important tool for understanding how our blood carries and releases oxygen that measures the strength by which oxygen binds to hemoglobin

How does the oxygen-hemoglobin dissociation curve change if a muscle is actively exercising?

exercise causes the oxygen-hemoglobin dissociation curve to shift to the right allowing more efficient unloading of oxygen to working muscle tissues

Why does fetal hemoglobin have a different oxygen-hemoglobin dissociation curve?

it has a higher affinity for oxygen, meaning it binds oxygen more readily and releases it less easily

Describe the 3 ways that carbon dioxide travels in the blood.

dissolved in the plasma, as bicarbonate ions in blood, and bound to the globin subunits of hemoglobin

Write out the chemical reactions that form the bicarbonate buffer system.

CO2 + H2O = H2CO3 = H+ + HCO3-

How does the level of carbon dioxide in the blood change the blood pH?

the more carbon dioxide the more acidic the blood pH

Which cellular processes require oxygen? (as in, why do cells need oxygen anyway?)

Electron Transport Chain (Oxidative Phosphorylation): Oxygen accepts electrons at the end of this chain in the mitochondrial membrane, allowing for efficient ATP production

What is normal blood pH?

7.4

Describe how hypoventilation leads to respiratory acidosis.

reduces the lungs ability to release CO2 leading to a buildup in the blood which drops the pH

Which part of the brain sets the respiratory rate?

medulla oblongata

Which nerves control ventilation?

phrenic nerves

Describe the role of the central chemoreceptors in regulating ventilation.

responds to changes in pH within the CSF

Where are the peripheral chemoreceptors?

aortic and carotid bodies

What role do peripheral chemoreceptor play in regulating ventilation?

primarily regulate ventilation by detecting low arterial oxygen

What do restrictive diseases do?

make it difficult to fully expand the lungs and inhale, reducing total lung capacity

What do obstructive diseases do?

make it difficult to exhale air due to narrowed or blocked airways

Define ingestion

the intake of food and liquids into the digestive tract through the mouth

Define digestion

the breakdown of food into smaller components that can be absorbed

Define absorption

nutrients move through the wall of the alimentary canal into blood or lymphatic vessels

Define secretion

the release of water, acid, buffers, and enzymes into the lumen of the alimentary canal to aid other digestive processes

Define propulsion

the movement of food through the digestive tract

Define peristalsis

one-way, wave-like contraction that propels food forward along the entire GI tract

Define segmentation

non-directional, churning action that mixes food with digestive juices and pushes it back and forth

What is mechanical digestion?

digestive organs physically break food down into smaller pieces (teeth and muscle contractions)

What is chemical digestion?

enzymes secreted by digestive organs catalyze reactions that break the chemical bonds within food particles until only small compounds remain (saliva, gastric juices, and bile)

List the structures of the digestive tract in order (and accessory organs)

oral cavity → pharynx → esophagus → stomach → small intestine → large intestine → rectum → anus (salivary glands, liver, gallbladder, pancreas)

Which organs of the digestive tract are covered with the serosa of the visceral peritoneum?

the intraperitoneal organs: stomach, liver, spleen, small intestine, pancreas, parts of large intestine

Describe how the digestive tract moves in and out of the peritoneum.

the peritoneum wraps around organs forming folds that suspend organs

Explain what intraperitoneal means

organs located entirely within the peritoneal cavity

Explain what retroperitoneal means

organs are partly or completely outside the peritoneal cavity

Describe the basic structure of a mesentery.

double folds of visceral peritoneum located around certain abdominal organs

Describe the basic function of a mesentery.

binds the intraperitoneal organs together and keep the small intestine in a particular shape that fits within the abdominopelvic cavity

Name the layers of the digestive tract from inner to outer

mucosa → submucosa → muscularis externa → adventitia

Describe the tissues found in the mucosa layer.

lamina: thin layer of loose connective tissue propria and muscularis mucosae: two thin sheets of smooth muscle

Describe the tissues found in the submucosa layer.

dense irregular connective tissue

Describe the tissues found in the muscularis externa layer.

two layers of smooth muscle

Describe the tissues found in the adventitia layer.

simple squamous epithelial tissue and loose connective tissue

Describe what happens during the voluntary phase of swallowing.

the tongue pushes the bolus posteriorly toward the oropharynx

Describe what happens during the pharyngeal phase of swallowing.

the bolus enters the oropharynx; the soft palate and epiglottis seal off the nasopharynx and larynx, respectively

Describe what happens during the esophageal phase of swallowing.

peristaltic waves move the bolus down the esophagus to the stomach

Describe the secretions of the mucous neck cells.

forms a thick, alkaline barrier coating the gastric surface, protecting the stomach wall from self-digestion by acid and pepsin

Describe the secretions of parietal cells.

secretes HCL to create a highly acidic environment to denature proteins, kill bacteria, and activate enzymes

Describe the secretions of chief cells.

secreted as inactive pepsinogen, which is activated by HCl into pepsin

Describe the secretions of DNES cells.

secrete gastrin, a hormone that stimulates parietal cells to produce more HCl

Describe the structure of a villus of the small intestine

a single-layered epithelium, a rich blood capillary network, and a central lacteal (lymph vessel) to transport absorbed nutrients rapidly

How are villi specialized for digestion and absorption?

increase the surface area of the small intestine maximizing the contact with food molecules

Describe the defecation reflex.

triggered by stretch receptors, it causes rectal muscles to contract and the internal anal sphincter to relax

Name the salivary glands.

parotid, submandibular, sublingual

Describe how lysozyme contributes to digestion

catalyzes the perforation of bacterial plasma membranes which allows bacteria-killing substances in the saliva to enter and kill the bacteria

Describe how secretory IgA contributes to digestion

binds specific antigens on pathogens and mediates their destruction

Describe how bicarbonate ions contributes to digestion

neutralize any acid from the stomach that regurgitates into the esophagus

Which enzyme is present in saliva, and what does that enzyme digest?

salivary amylase digests carbs

Describe the role of the pancreas in digestion.

secretes enzymatic juice into the small intestine to break down proteins, fats, and carbohydrates; produces bicarbonate to neutralize stomach acid

Which cells of the pancreas perform this function?

acinar cells (secreting enzymes) and duct cells (secreting bicarbonate)

Where do the secretions of the pancreas enter the digestive tract?

the duodenum

Which enzymes are present in pancreatic juices?

pancreatic lipase, pancreatic amylase, trypsin, chymotrypsin, carboxypeptidase, and nucleases

What does pancreatic lipase digest?

lipids

What does pancreatic amylase digest?

carbs

What does trypsin, chymotrypsin, carboxypeptidase digest?

proteins

What do nucleases digest?

nucleic acids

Why is it necessary for pancreatic juices to contain bicarbonate ions?

neutralizes acidic chyme from the stomach, creating a suitable pH for these enzymes to function

What is the function of bile in digestion?

digestion and absorption of lipids and it is the mechanism by which the liver excretes wastes and other substances that the kidneys cannot excrete

How does bile travel from the liver to the digestive tract?

it flows through the hepatic ducts into the common bile duct, where it is either stored in the gallbladder or released directly into the duodenum to aid in digestion

What happens when the hepatopancreatic sphincter is closed? (What happens to bile when it is stored in the gall bladder?)

it is forced backward up the common bile duct and cystic duct to be stored and concentrated in the gallbladder

Name the enzymes involved in the digestion of carbs

salivary amylase, pancreatic amylase, brush border enzymes

Where does digestion occur for carbs?

mouth, small intestine

How do carbs reach the bloodstream?

through intestinal mucosal cells into the capillaries