Midterm 3 Wilson Flashcards
What are the parts of the respiratory system?
a) Nose/Parnanasal sinuses
b) Pharynx
c) Larynx
d) Trachea
e) Bronchi
f) Lungs & Pleurae
What are the four processes of respiration?
1) Pulmonary Ventilation
2) External Respiration
3) Transport of Respiratory Gases
4) Internal Respiration
Which of the four processes of respiration are done by the respiratory system?
Pulmonary Ventilation and External Ventilation
What other system is involved?
Circulatory system
What are the two main functional divisions of the respiratory system?
1) Conducting Zone
2) Respiratory Zone
What is in the conducting zone?
Consists of a series of cavities and tubes that conduct air into the lungs (nose, pharynx, larynx, trachea, bronchi, bronchiole, and terminal bronchioles.
What is in the Respiratory zone?
Consists of the area where gas exchange occurs (respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli
What are the two main anatomical divisions of the respiratory system?
1) Upper respiratory tract
2) Lower respiratory tract
What is in each of the two main anatomical divisions of the respiratory system?
- Upper respiratory tract (above vocal cords): Nose, Pharynx (throat), and Larynx (voicebox)
- Lower Respiratory tract (below vocal cords): Trachea (windpipe), bronci (airways), and Lungs & Pleurae (membranes)
What are the functions of the nose?
- airway
- warms, moistens, and filter incoming air
- receives olfactory stimuli
- serves as large, hollow resonating chambers to modify speech sounds
What are the divisions of the nose?
- External nose
2. Nasal Cavity
What are the main parts of the external nose?
Skin, nasal bones, & cartilage lined with mucous membrane (openings called external nares or nostrils)
- Root
- Bridge
- dorsum nasi
- apex
- nares (nostrils=bounded laterally by the flared alae)
Describe the pathway of air through the nose and nasal passageway and its parts.
- Nasal cavity divided by nasal septum; roof is ethmoid bone; floor is hard palate
- Air enters through nares into vestibule
- Conchae/meatus are projections/grooves on lateral walls that open to posterior nasal aperature
- The internal portion communicates with the paranasal sinuses and nasopharynx through the internal nares
What are nasal polyps?
Outgrowths of the mucous membranes which are usually found around the openings of the paranasal sinuses.
What is the nasal epithelium of the nasal passageway?
Contains olfactory receptors and mucus producing cells (secretes mucus)
What is the respiratory epithelium of the nasal passageway?
Pseudostratified columnar cells with cilia to move stuff (contains lysosome: antibacterial)
what is the function of Nasal epithelium?
Secretes mucus
what is the function of Nasal epithelium?
The olfactory epithelium is a layer of odor-sensitive cells located inside the depths of the nose. These cells react to odors as they enter the nose, sending signals to the olfactory bulb.
What is the function of the respiratory epithelium?
This lining acts as a barrier between the air coming into the body and the inner tissues of the respiratory mechanism, and it also serves to warm, clean and moisten the air in preparation for its arrival in the lungs.
What are the paranasal sinuses?
a group of four paired air-filled spaces that surround the nasal cavity
What is the function of the paranasal sinuses?
Lighten skull, warm & moisten air & resonate voice
What are the functions of the pharynx?
- Connects nasal cavity & mouth to larynx & esophagus
- Passageway for food and air
- resonating chamber for speech production
- tonsil (lymphatic tissue) in the walls protects entryway into body
What are the divisions of the pharynx?
- Nasopharynx
- Oropharynx
- Laryngopharynx
What is the role of the nasopharynx in respiration?
Passageway for air only
• Psuedostraified ciliated columnar epithelium (not used to move food) with goblet cells (produce mucus)
What is the role of the oropharynx in respiration?
Common passageway for food and air (abrasion from food: may layers)
• Stratified squamous epithelium
What is the role of the Laryngopharynx in respiration?
Common passageway for food & air; ends as esophagus inferiorly
• Stratified squamous epithelium
What are the functions of the larynx?
- Provide a patent (open) airway
- Act as a switching mechanism to route air and food into proper channels
- Voice production
What are the divisions of the larynx?
- Epiglottis
- Hyaline cartilages: thyroid, laryngeal prominence (adam’s apple), cricoid cartilage, arytenoid, cuneiform, corniculate
- Vocal Ligaments: Vocal cords, glottis, vestibular folds
Which anatomical divisions of the larynx play a role in swallowing?
Epiglottis
Which anatomical divisions of the larynx play a role in Voice production
Vocal ligaments
What role does the larynx play in swallowing?
During swallowing, larynx moves upward; epiglottis bends to cover glottis
What are the vocal cords?
Two pair of folds (superior and inferior)
What is the difference between the false and true cords?
False vocal cords: • Structure: mucous membranes • Function: holding breath True vocal cords: • Structure: Mucous membranes and elastic ligaments attached to cartilage • Function: set up sound waves
How do vocal cords play a role in speech production?
The vocal folds vibrate, producing sound as air rushes up from the lungs
How do various components of speech get produced (e.g. loudness, pitch)?
Pitch is controlled by tension on vocal folds
• Pulled tight produces higher pitch
• Male vocal folds are thicker and longer so vibrate more slowly producing a lower pitch
Whispering is forcing air through almost closed glottis—oral cavity alone forms speech.
What are the functions of the trachea?
- The cartilage rings keep the airway open
2. The cilia of the epithelium sweep debris away from the lungs and back to the throat to be swallowed.
What are the histological divisions of the trachea?
- Mucosa
- Submucosa
- Hyaline cartilage
- Adventitia
What is the role of each of the histological divisions?
- Mucosa: propel debris-laden mucus toward the pharynx
- Submucosa: secretes mucus
- Hyaline cartilage: allow stretch and movement inferiorly during inspiration and recoil during expiration.
- Adventitia: prevent trachea from collapsing
What is mucosa, submucosa, adventitia?
- Mucosa: goblet cell-containing pseudostratified epithelium (ciliated)
- Submucosa: CT layer deep to the mucosa, contains seromucous glands that help produce “sheets” within the trachea
- Adventitia: the outermost layer of connective tissue
What is a tracheostomy?
Incision in trachea below cricoid cartilage if larynx is obstructed
How does a tracheostomy compare to intubation?
Intubation is passing a tube from mouth or nose through larynx and trachea (no incision required)
What are the functions of the bronchi/bronchial tree?
- Conduction tubes
2. Respiratory zones: alveolar ducts where gas exchange takes place
What are the divisions of the bronchi / bronchial tree?
- Trachea
- primary bronchi
- secondary bronchi
- tertiary bronchi
- bronchioles
- terminal bronchioles
Describe how the histological features of the bronchi change as it goes from conducting to respiratory zone.
- In conduction zone: cartilage ring replaced by plates; epithelium thins, cilia sparse (decreases), smooth muscle increases (to control size of bronchioles); not as much cartilage
- In Respiratory zone: Alveoli simple squamous epithelium (Type 1 cells exchange; Type II secrete surfactant fluid) and capillaries = respiratory membrane
What are the cell types in the alveoli and what do they do?
- Type I alveolar cells
• Simple squamous cells where gas exchange occurs - Type II alveolar cells (septal cells)
• Free surface has microvilli
• Secrete alveolar fluid containing surfactant - Alveolar dust cells
• Wandering macrophages remove debris
What is respiratory distress syndrome?
a disorder of premature infants in chich the alveoli do not have sufficient surfactant to remain open.
What is surfactant?
Like detergent: it’s roles is to break up hydrogen bonds
What are the functions of the lungs?
Site of gas exchange
What are the divisions (anatomy) of the lungs?
- Pleurae (membranes)
- Gross anatomical features (hilium, cardiac notch, lobes, bronchopulmonary segments, lobules)
- Blood supply
What are the pleura of the lungs called and where is each?
- Visceral pleura: covers lungs
- Parietal pleura: lines ribcage & covers upper surface of diaphragm
- Pleural cavity: space between the visceral and parietal pleura where pleural fluid is made.
What is pleurisy?
Inflammation of membrane
describe the gross anatomical features of the lungs.
- Base, apex (cupula), costal surface, cardiac notch
- Oblique & horizontal fissure in right lung results in 3 lobes
- Oblique fissure only in left lung produces 2 lobes
Why is the right lung bigger?
Because the left lung has the cardiac notch to make room for the heart
What is the hilum?
An indentation on the mediastinal surface of each lung thru which pulmonary and systemic blood vessels, bronchi, lymphatic vessels, and nerves enter and leave the lungs.
Besides vessels, what else joins the lungs at the root?
bronchi, lymphatic vessels, and nerves enter and leave the lungs.
Why does the lung have two blood supplies and what are they?
- Pulmonary trunk: deoxygenated blood arrives through this from the right ventricle of the heart.
- Bronchial arteries: these branch off of the aorta to supply oxygenated blood to lung tissues
What is ventilation-perfusion coupling?
In the lungs vasoconstriction in response to hypoxia diverts pulmonary blood from poorly ventilated areas to well ventilated areas.
What are the transpulmonary / intrapulmonary / and intrapleural pressures and how does this deter lungs from collapsing?
Transpulmonary pressure (4mm hg) is the difference between intrapulmonary (760 mm hg) and intrapleural (756 mm hg) pressures.
Transpulomary pressure keeps air spaces for lung open. Lungs do not collapse because of negative pressure in the intrapleural space
When would lungs collapse?
When P_ip equalizes with the intrapulmonary (or atmospheric) pressure
What is pulmonary ventilation?
Breathing
As you inspire, the volume in the lungs increases and the pressure decreases. As you expire, the volume in the lungs decreases and the pressure increases.
As you inspire, the volume in the lungs increases and the pressure decreases. As you expire, the volume in the lungs decreases and the pressure increases.
How do the lungs change volume during inspiration / expiration
Inspiration: chest expands increasing volume
Expiration: Chest compresses decreasing volume
What muscles are involved in inspiration/exhalation?
Diaphragm and external intercostal muscles
What is quiet inspiration and how do pressures change during this process?
Quiet inspiration is the normal breathing (when at rest) you do without thinking about it. Intrathoracic pressure falls and 2-3 liters is inhaled.
What is the difference between quiet and forced inhalation?
Where quiet inhalation is the normal breathing when at rest, forced inhalation is the breathing that occurs when you are excercising or have some COPD.
Which muscles differ in quiet and forces inhalation?
- Quiet inspiration utilizes the diaphragm and external intercostal muscles.
- Forced inhalation uses the same muscles as well as accessory muscles (sternocleidomastoids, scaleness, and pectoralis minor)
What is quiet expiration and how do pressures change during this process?
Quiet expiration is a passive process with no muscle action. (inhalation, muscles relax)
Thoracic and intrapulmonary volume decreases and the pressure increases.
What is the difference between quiet and forced exhalation?
While quiet exhalation is a passive process, forced exhalation is an active procress
Which muscles differ in quiet and forced exhalation?
- Quiet exhalation uses no muscles
* Forces exhalation uses abdominal wall muscles
How do changes in pressure result in breathing?
- Alveolar pressure decreases & air rushes in (inhalation)
* Alveolar pressure increases & air rushes out (exhalation)
What 3 factors influence ventilation?
- Airway resistance
- Alveolar surface tension
- compliance
What does Airway Resistance mean?
Friction and drag reduce ventilation
What does Alveolar Surface Tension mean?
Water molecules at alveolar surface tend to stick together and prevent ventilation
What does Compliance mean?
Lung tissue is stretchy and distensible but may be diminished
How does airway resistance affect ventilation?
Resistance to airflow depends on the airway size. If the airway diameter is large then the resistance is low and air flows freely, if the airway diameter is small then the resistance is high and air flow is restricted.
Where is resistance greatest in the respiration pathway?
Medium-sized bronchi
How does an asthma attack affect resistance in the respiration pathway?
During an asthma attack, the bronchioles are constricted causing high resistance
What is alveolar surface tension?
The surface tension that exists between water molecules (H bonds) inside lung
What is Surfactant?
A detergent like compound to reduce surface tension
Which cells produce surfactant?
Type II alveolar cells
What is respiratory distress syndrome?
A disorder of premature infants in which the alveoli do not have sufficient surfactant to remain open
What is lung compliance?
Ease with which lungs & chest wall expand (depends upon elasticity of lungs & surface tension)
What disorders can reduce compliance?
- Tuberculosis
- Pulmonary edema
- paralysis
What are the 4 types of respiratory volumes?
- Tidal Volume
- Inspiratory Reserve
- Expiratory Reserve
- Residual Volume
What does Tidal Volume measure?
amount of air moved during quiet breathing (500 mL)
What does Inspiratory reserve volume measure?
The amount of air that can be inspired forcibly beyond the tidal volume (3100 mL)
What does Expiratory Reserve volume measure?
The amount of air that can be expired forcibly after a normal tidal volume expiration (1200 mL)
What does Residual volume measure?
Permanently trapped air in the lungs; amount of air left in lungs even after the most strenuous expiration (1200mL)
What is the difference between vital and total lung capacity?
These are the sums of the other volumes
• Vital capacity is the sum of Inspiratory reserve volume, tidal volume, and expiratory reserve volume (4800 mL)
• Total lung capacity is the sum of all 4 of the respiratory volumes (6000 mL)
What is the minute ventilation rate?
Amount of air moved in a minute
How does one measure respiratory volumes?
With a spirometor
How can breathing rates change and the names for the changes?
- Apnea: breath holding (sleep apnea)
- Dyspnea: painful or difficult breathing
- Tachypnea: rapid breathing rate
- Costal Breathing: (uses intercostal & extracostal muscles) need for increased ventilation (as with exercise)
- Diaphragmatic Breathing: usual mode of operation to move air by contracting and relaxing the diaphragm to change the lung volume
- Modified Respiratory Movements: Used to express emotions and to clear air passageways
What are some non-respiratory changes in ventilation?
- Cough
- Sneeze
- Crying
- Laughing
- Hiccups
- Yawn
What are the three steps in gas exchange and where does each occur?
- Ventilation:
- External (pulmonary) respiration: in lungs
- Internal (tissue) respiraton: in tissues
What three factors determine the movement of gases in our bodies?
- Composition of air and partial pressure of gasses in atmosphere, in alveoli air, and in expired air (Dalton’s law of partial pressure)
- Gas’s solubility (Henry’s Law)
- Hemoglobin structure and affinity to O2 and CO2
What is Dalton’s law and how does this determine how gases move in our bodies?
- Air is composed of 21% O2, 79% N2, and .04% CO2
- Each gas in a mixture of gases exerts its own pressure=partial pressure (p)
- Total pressure is sum of all partial pressures
Partial pressure gradients (differences) exist between different areas of the body that will promote the movement of gases
How do gradients vary across the body?
the Alveoli have a higher pressure gradient of O2 and lower pressure gradient of CO2. Where as tissues have a lower pressure gradient of O2 and higher CO2 pressure gradient.
How does the gradient variations across the body drive internal and external respiration processes?
allows tissues to receive the O2 they need while getting rid of CO2
What is Henry’s law?
States that the quantity of a gas that will dissolve in a liquid depends upon the amount of gas present and it’s solubility coefficient.
How does Henry’s law determine how gases move in the body?
Gases with a higher concentration will move faster than ones with lower concentration
What is a hyperbaric chamber and how does that increase gas solubility?
It’s a chamber that contains O2 gas at pressures higher than 1 atm are used to force greater-than-normal amount of O2 in the blood. This increases solubility as the concentration of O2 is higher.
what are four factors that affect respiration rate of diffusion?
- Concentration gradient
- Surface area
- Diffusion difference
- Molecular weight & solubility
How can each of the four factors that affect respiration rate of diffusion change?
- Concentration gradient: the greater the difference, the faster the rate of diffusion
- Surface area: disease or injury that decrease that surface area
- Diffusion difference: build up of fluid in the lungs increases the diffusion distance
- Molecular weight & solubility: Low Po2 will usually be a problem before High Pco2 in the blood
What is ventilation/perfusion coupling?
In the lungs, vasoconstriction in response to hypoxia diverts pulmonary blood from poorly ventilated areas to well ventilated areas.
How does ventilation/perfusion coupling keep our body in homeostasis?
the changing diameter of locar bronchioles and arterioles synchornizes alveolar ventilation and pulmonary perfusion
• Po2 controls perfusion by changing arteriolar diameter
• Pco2 controls ventilation by changing bronchiolar diameter
How does Hemoglobin play a role in gas exchange?
O2 (98%) binds to the heme to be carried from the lungs to the tissues and the globin carries some CO2 (20%)
Which gases does hemoglobin play a role in?
O2 and CO2
How does Oxygen saturation change with partial pressure?
It increases as partial pressure increases
What are some differences between an exercising and a resting muscle, and why do each get different amounts of oxygen?
Resting muscles have more partial pressure than exercising muscles so therefore have less saturation..
Know three ways carbon dioxide is transported in the blood.
- Dissolved in plasma (7%)
- Combined with globin part of Hb molecule forming carbaminohemoglobin (23%)
- As part of bicarbonate ion (70%)
How does this differ from Oxygen?
Oxygen is carried on heme (98%)
Why is carbon monoxide poisoning bad?
it binds strongly to iron in hemoglobin. Once it attaches, it is very difficult to release. It sticks to you hemoglobin and takes up all of the oxygen bind sites and causes your blood to lose it’s abliity to transport oxygen.
How does bicarbonate regulate pH of blood?
HCO3 combines with H+ to remove excess H+ or HCO3 dissociates by releasing H+ when not enough H+
where are the respiratory centers in the central nervous system?
- Medullary center
* Pontine Center
What are the 2 medullary centers and what does each do?
- Dorsal respiratory group: sensory inputs from periphery
* Ventral respiratory group: motor rhythm generation (exciting breathing muscles)
What is the center in the pons and what role does it play in respiration?
Pontine Center: smooth respiratory movement; modifiers for breathing (indirect; fine tunes)
What are the two factors that regulate respiration?
- Higher brain centers (voluntary control)
* Chemical factors (involuntary control)
What higher brain regions can regulate respiration ?
(cortical influences) Hypothalamus & primary motor cortex
What stimuli overrides voluntary control of breathing?
Increased H+ and CO2
What is the pulmonary irritant reflex?
Reflex constriction of air passages (cough, sneeze, etc) due to an irritant.
What is the Inflation reflex?
Stretch receptors, if not activated, start breathing.
What are the chemical factors involved in regulating breathing?
- Central chemoreceptors in the medulla
* Peripheral chemoreceptors
Which is a more potent stimulus – low Oxygen or high CO2?
High CO2
Where are the central chemoreceptors and peripheral receptors?
- Central chemoreceptors: in medulla
* Peripheral chemoreceptors: wall of aorta and walls of common carotid arteries
What is hypercapnia?
Slight increase in pCO2 is noticed
What is Hyperventilation?
Excessive ventilation, characterized by low Pco2 and alkalosis
How does a negative feedback system regulate breathing?
hypoventilation
What is hypoventilation?
Under breathing
What are two factors that increase and decrease ventilation?
- Limbic system
* Proprioceptor activity
What are some ways respiration can be adjusted?
- Exercise
- High altitude
- Aging
What changes occur during exercise?
As blood flow increases with a lower O2 and higher CO2 content, the amount passing thru the lung increases and is matched by increased ventilation and oxygen diffusion capacity as more pulmonary capillaries open.
What are 3 neural factors involved in exercise-respiration?
- Psychological stimuli
- Cortical Motor activation
- proprioceptors
What changes occur when one smokes?
Easily “winded” with moderate exercise (less ventilation, less perfusion)
How does this affect the lungs?
- Nicotine constricts terminal bronchioles (less air in alveoli
- Carbon monoxide in smoke binds to hemoglobin
- Irritants in smoke cause excess mucus secretion
- Irritants inhibit movements of cilia (sometimes killing cells)
- In time, destroys elastic fibers (reduce compliancy) in lungs and leads to emphysema
How does high altitude lead to changes in respiration?
As you get higher there is less oxygen, as a result ventilation increases as the brain attempts to restore gas exchange to previous levels.
What are some short and long term effects of high altitude?
- short term effects: acute mountain sickness (nausea, headaches, shortness of breath, dizziness)
- Long term effects: will lead to acclimatization and EPO production (increased RBC’s)
What is acclimatization?
Adaptive response
What happens to EPO levels?
they increase
How does aging change respiration capabilities?
- Respiratory tissues and chest wall become more rigid
- Vital capacity decreases to 35% by age 70
- Decreases in macrophage activity
- Diminished ciliary action
- Decrease in blood levels of O2
- Result is age-related susceptibility to pneumonia or bronchitis
What are the homeostatic imbalances related to the respiratory system and what part of the respiratory system is affected?
- • Pneumothorax - membranes
- Asthma – conducting zone
- Hypoxia – respiratory zone
- COPD – respiratory zone
- Emphysema – respiratory zone
- Chronic bronchitis – conducting zone
- Bronchogenic carcinoma – conducting zone
- Pneumonia – respiratory zone
- Coryza (common cold) – conducting zone
- Tuberculosis – membranes
- Pulmonary edema – respiratory zone
- Cystic fibrosis – conducting zone
- Asbestos – membranes
- Sudden infant death syndrome (SIDS) – unknown
What is the difference between the effects of bronchitis and emphysema on the alveoli?
- Emphysema: distinguished by permanent enlargement of the alveoli, accompanied by destructionof the alveolar walls.
- Bronchitis: chronic production of excessive mucus inpairs ventilation and gas exchange
What are the functional segments of the digestive system?
- Mouth/pharynx
- Esophagus
- Stomach
- Small intestines
- Large instestines
What are the accessory structures of the digestive system?
- Teeth
- Toungue
- Salivary glands
- Liver
- Gallbladder
- pancreas
What are the anatomical features responsible for some of the digestive system functions?
- Mouth: bite, chew, swallow, limited lipid & carb digestion
- Pharynx & esophagus: transport
- Stomach: mechanical disruption: absorption of water & alcohol, protein & lipid digestion
- Small Intestines: most chemical & mechanical digestion & absorption
- Large intestines: absorb electrolytes & vitamins (B and K)
- Rectum & anus: defecation
Describe the stimuli and controls of digestive activity.
- Mechanical & chemical stimuli (internal to GI Tract)
• Stretch, osmolarity, pH sensors monitor conditions that promote reflexive activity that:
o Activate glands/hormones
o Stimulate smooth muscle (will promote short reflexes; local) - Extrinsic control: autonomic nervous system
• Enteric nervous system controls short reflexes; long reflexes controlled by extrinsic signals
What are the 6 processes that occur in the digestive system and define them:
• Ingestion: taking food into the mouth (eating
• Secretion: the release, by cells within the walls of the GI tract and accessory organs, of water, acid, buffers, and enzymes into the lumen of the tract
• Mixing/propulsion: result from the alternating contraction and relaxation of the smooth muscle
• Digestion: breakdown of food
o Mechanical: consists of movements (smooth muscle contraction) of the GI tract that aid in chemical digestion
o Chemical: is a series of catabolic (hydrolysis) reactions that break down large carbohydrate, lipid, and protein food molecules into smaller molecules that are usable by body cells
• Absorption: the passage of end products of digestion from the GI tract into blood or lymph for distribution to cells
• Defecation: emptying of the rectum, eliminating indigestible substances from the GI tract
What are the membranes of the digestive system called?
Peritoneum
What is mesentery?
Double layer of membrane; back to back
What is peritonitis?
Inflammation of the peritoneum
What are omenta?
Tethers stomach to other digestive organs
Name at least three omenta
- Greater omentum
- Mesentery
- Lesser omentum
What are some common histological features of the digestive tract?
Walls of the alimentary canal have the same layers
How many layers are there in the digestive tract?
4`
What are the 4 layers in the digestive tract?
- Mucosal layer
- Submucosa:
- Muscularis externa:
- Serosa: visceral peritoneum
What is the basic feature of the Mucosa layer?
Has 3 layers:
Epithelium
• Stratified squamous (in mouth, esophagus, & anus) simple columnar in the rest.
Lamina Propria
• Thin layer of loose CT, contains BV and lymphatic tissue
Muscularis mucosae
• Thin layer of smooth muscle
What is the basic feature of the submucosa Layer?
Loose connective tissue (areolar CT)
Meissner’s plexus (submucousal nerve plexus (enternic nervous system)
• Parasympathetic innervation
What is the basic feature of the muscularis externa layer?
- Skeletal muscle = voluntary control
* Smooth muscle = involuntary control
What is the basic feature of the serosa layer?
- Areolar CT
- Extension of visceral peritoneum
- Covers all organs and walls of cavities not open to the outside of the body
- Secretes slippery fluid
- Consists of connective tissue covered with simple squamous epithelium
In the mucosal layer, where does the type of epithelial cell changes and why
The mouth, esophagus, and anus have stratified squamous epithelium to protect against abrasion. The rest of the tube is simple columnar epithelium rich in mucus-secreting cells.
What is adventitia and where is it found?
ordinary fibrous CT. Found in esophagus and retroperitoneal organs (on side facing the peritoneal cavity)
In which layers of the digestive tract does the enteric nervous system appear?
Submucosa and Muscularis Externa
What are the anatomical features of the mouth?
- Lips (labia) and cheeks
- Vestibule
- Oral cavity proper
What function does the mouth play in digestion?
- Ingestion
- Digestion
- Propulsion