ANAT100- Block Theory 3

Primary functions of the respiratory system

Gas exchange, gas conditioning, sound production, olfaction, and defense.

Two cyclic phases of respiration

Inspiration (oxygen-rich air enters the lungs) and expiration (oxygen-poor air leaves the lungs).

External respiration

The exchange of gases between the air in the lungs and the blood in pulmonary capillaries.

Internal respiration

The exchange of gases between blood in systemic capillaries and body tissues.

Gas conditioning

It warms, humidifies, and cleanses air to prevent lung damage.

Location of gas conditioning

In the nasal cavity and paranasal sinuses.

Defense against pathogens in the respiratory system

Mucus, cilia, immune cells, and nasal hairs trap and remove pathogens.

Role of cilia in the respiratory tract

They beat in a coordinated motion to move mucus and trapped particles out of the airways.

Conducting portion of the respiratory system

Nose, nasal cavity, paranasal sinuses, pharynx, larynx, trachea, bronchi, and terminal bronchioles.

Respiratory portion of the respiratory system

Respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.

Four paranasal sinuses

Frontal, maxillary, ethmoid, and sphenoid sinuses.

Function of the paranasal sinuses

They lighten the skull, aid in gas conditioning, and serve as resonance chambers for speech.

Epithelium lining most of the nasal cavity

Pseudostratified ciliated columnar epithelium.

Contribution of nasal conchae to respiration

They create turbulence, increasing air contact with the mucosa for better conditioning.

Function of goblet cells in the nasal cavity

They secrete mucus that traps debris and humidifies incoming air.

Role of the nasal septum

It divides the nasal cavity into left and right halves.

Structure connecting the nasal cavity to the pharynx

The choanae.

Function of olfactory epithelium

It contains olfactory receptor neurons responsible for detecting airborne molecules and transmitting smell signals.

Boundaries of the nasal cavity

Roof (ethmoid bone), floor (hard palate), medial wall (nasal septum), and lateral wall (nasal conchae).

Function of nasal hairs (vibrissae)

They trap large particles and debris before air enters the respiratory tract.

Three regions of the pharynx

Nasopharynx, oropharynx, and laryngopharynx.

Epithelium lining the nasopharynx

Pseudostratified ciliated columnar epithelium for air filtration.

Epithelium lining the oropharynx and laryngopharynx

Stratified squamous epithelium for protection during swallowing.

Primary function of the epiglottis

To prevent food from entering the trachea during swallowing.

Three major cartilages of the larynx

Epiglottis, thyroid cartilage, and cricoid cartilage.

Contribution of the thyroid cartilage to voice production

It provides attachment for vocal cords.

Function of the true vocal cords

They vibrate to produce sound.

Function of the false vocal cords

They protect the true vocal cords and help close the larynx during swallowing.

Effect of changing tension on the vocal cords

Increased tension produces a higher pitch, while decreased tension produces a lower pitch.

Structure connecting the pharynx to the trachea

The larynx.

Shape of tracheal cartilages

C-shaped instead of complete rings to provide structural support while allowing flexibility for swallowing.

Epithelium lining the trachea

Pseudostratified ciliated columnar epithelium.

Pseudostratified ciliated columnar epithelium

Lines the trachea.

Carina

Marks the bifurcation of the trachea into the primary bronchi and triggers the cough reflex.

Primary bronchi

The right bronchus is wider, shorter, and more vertical, making it more likely for foreign objects to enter.

Levels of bronchi

Primary, secondary (lobar), and tertiary (segmental) bronchi.

Terminal bronchioles

The last part of the conducting zone.

Respiratory bronchioles

The first part of the respiratory zone.

Alveolar ducts

They transport air to alveolar sacs where gas exchange occurs.

Simple squamous epithelium

Lines alveoli.

Surfactant

Reduces surface tension, preventing alveolar collapse.

Pulmonary capillaries

Surround alveoli and facilitate the diffusion of oxygen into the blood and carbon dioxide out of the blood.

Right lung lobes

Three (superior, middle, and inferior).

Left lung lobes

Two (superior and inferior).

Cardiac notch

An indentation in the left lung that accommodates the heart.

Pleural membrane

Secretes pleural fluid to reduce friction and allow smooth lung expansion.

Layers of the pleura

The visceral pleura (covers the lung surface) and parietal pleura (lines the thoracic cavity).

Pleural cavity

The space between the visceral and parietal pleura containing pleural fluid.

Diaphragm

Contracts to increase thoracic volume, causing inspiration.

Diaphragm during exhalation

Relaxes, reducing thoracic volume and causing expiration.

Lung surfaces

Costal (contacts ribs), mediastinal (contacts the heart and major vessels), and diaphragmatic (rests on the diaphragm).

Hilum of the lung

The entry and exit point for blood vessels, bronchi, and lymphatics.

Alimentary canal

Digestive tract.

Structures of the alimentary canal

Mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus.

Accessory digestive organs

Tongue, teeth, salivary glands, liver, gallbladder, and pancreas.

Histological layers of the digestive tract

Mucosa, submucosa, muscularis externa, and serosa/adventitia.

Esophagus epithelium

Stratified squamous epithelium for protection against friction.

Stomach epithelium

Simple columnar epithelium with mucus-secreting cells for acid protection.

Function of the submucosa

Contains blood vessels, lymphatics, glands, and nerve plexuses that support digestion.

Muscularis externa

Has circular and longitudinal smooth muscle layers for peristalsis.

Difference between serosa and adventitia

Serosa is a slippery serous membrane covering organs, while adventitia is loose connective tissue anchoring organs.

Function of the enteric nervous system

Controls gut motility, secretion, and local reflexes independent of the central nervous system.

Regions of the oral cavity

The vestibule (space between cheeks/lips and teeth/gums) and the oral cavity proper.

Hard palate

It is made of bone.

Soft palate

It is muscular and ends in the uvula.

Major salivary glands

Parotid, submandibular, and sublingual glands.

Parotid gland secretion

Serous fluid with digestive enzymes.

Submandibular gland secretion

Mixed serous and mucous secretions.

Sublingual gland secretion

Mostly mucous secretions for lubrication.

Intrinsic muscles of the tongue

They change the shape of the tongue.

Extrinsic muscles of the tongue

They move the tongue during chewing and speech.

Lingual frenulum

It anchors the tongue to the floor of the mouth.

Types of papillae on the tongue

Filiform, fungiform, circumvallate, and foliate.

Human teeth sets

Deciduous (baby) teeth have 20, and permanent teeth have 32.

Dental formula for deciduous teeth

2 incisors, 1 canine, and 2 molars per quadrant.

Dental formula for permanent teeth

2 incisors, 1 canine, 2 premolars, and 3 molars per quadrant.

Types of tonsils

Palatine, pharyngeal (adenoids), and lingual tonsils.

Function of the tonsils

They act as immune defense structures in the pharynx.

Tonsils removed during tonsillectomy

Palatine tonsils.

Role of enamel in teeth

It is the hardest substance in the body, protecting the tooth surface.

Function of dentin

It provides structural support beneath enamel.

Cementum contribution to tooth function

It anchors the tooth to the periodontal ligament.

Pulp cavity

It is the innermost part of the tooth containing nerves and blood vessels.

Function of the esophagus

It transports food from the pharynx to the stomach via peristalsis.

Function of the lower esophageal sphincter

It prevents stomach acid from refluxing into the esophagus.

Regions of the stomach

Fundus, body, and antrum.

Function of rugae in the stomach

They allow the stomach to expand after eating.

Layers of the stomach's muscularis externa

Outer longitudinal, middle circular, and inner oblique.

Role of gastric glands

They secrete digestive enzymes and acids.

Parietal cells secretion

Hydrochloric acid (HCl) for digestion and intrinsic factor for vitamin B12 absorption.

Chief cells secretion

Pepsinogen, which is activated to pepsin for protein digestion.

Mucus-secreting cells in the stomach

They produce a protective mucus layer to prevent acid damage.

Role of the pyloric sphincter

It regulates the passage of chyme from the stomach to the small intestine.

Sections of the small intestine

Duodenum, jejunum, and ileum.

Structures increasing surface area for absorption in the small intestine

Villi, microvilli, and plicae circulares.

Peyer's patches

They are lymphoid tissue aggregates in the ileum that protect against pathogens.

Intestinal glands (crypts of Lieberkühn)

They secrete digestive enzymes and mucus.

Function of the large intestine

Water absorption, fecal formation, and gut microbiome activity.

Sections of the colon

Ascending, transverse, descending, and sigmoid colon.

Function of the rectum

It stores fecal matter before defecation.