week 7 quiz

RESPIRATORY SYSTEM

1. Functions of the Respiratory System

• Gas exchange – Oxygen in, carbon dioxide out.

• Regulation of blood pH – By controlling CO₂ levels.

• Voice production – Air moving through the larynx produces sound.

• Olfaction – Smell receptors in the nasal cavity detect odors.

• Protection – Mucus, cilia, and other structures help filter and clean incoming air.

2. Conducting Division of the Respiratory System

Function:

• The conducting division carries air to and from the lungs.

• Also filters, moistens, and warms the air.

• NO gas exchange occurs here.

Structures (in order of airflow):

• Nasal cavity – Contains nasal conchae that increase surface area and warm, humidify, and clean the air.

• Pharynx – Shared with digestive system; divided into:

  • Nasopharynx – Only for air passage.

  • Oropharynx – Air and food passage; lined with stratified squamous epithelium for protection.

  • Laryngopharynx – Air and food passage; connects to esophagus and larynx.

• Larynx – "Voice box"; contains vocal cords.

  • Epiglottis – Prevents food from entering the trachea during swallowing.

  • Thyroid cartilage – Protects vocal cords; Adam’s apple.

  • Cricoid cartilage – Complete ring of cartilage below the thyroid cartilage.

  • True vocal cords – Produce sound; controlled by muscles.

• Trachea – "Windpipe"; lined with ciliated pseudostratified columnar epithelium and goblet cells (produce mucus).

  • C-shaped cartilage rings – Keep airway open.

• Bronchi – Branch off from the trachea into the lungs.

  • Primary (main) bronchi – One to each lung.

  • Secondary (lobar) bronchi – One to each lobe (3 on right, 2 on left).

  • Tertiary (segmental) bronchi – Smaller branches.

• Bronchioles – Smallest airways; contain smooth muscle to regulate airflow.

3. Respiratory Division of the Respiratory System

Function:

• Site of gas exchange.

Structures:

• Respiratory bronchioles

• Alveolar ducts

• Alveolar sacs

• Alveoli – Tiny air sacs where gas exchange occurs.

  • Type I cells – Simple squamous epithelium for gas exchange.

  • Type II cells – Produce surfactant (reduces surface tension).

  • Macrophages – Immune defense.

4. Pulmonary Ventilation (Breathing)

• Inhalation:

  • Diaphragm and external intercostals contract → Thoracic cavity expands → Lung pressure decreases → Air moves in.

• Exhalation:

  • Diaphragm and intercostals relax → Thoracic cavity shrinks → Lung pressure increases → Air moves out.

• Forced Exhalation:

  • Internal intercostals and abdominal muscles contract.

5. How Air is Filtered, Warmed, and Moistened

• Nasal conchae – Increase surface area and create turbulence.

• Mucus and cilia – Trap debris and sweep it toward the pharynx.

• Blood vessels in nasal cavity – Warm the air.

• Goblet cells – Secrete mucus to moisten the air.

6. How Sound is Produced

• Air passing over vocal cords → Vibration → Sound.

• Pitch – Controlled by tension of vocal cords.

• Volume – Controlled by force of air passing over vocal cords.

7. Protection of the Respiratory System

• Nasal hairs – Trap large particles.

• Mucus and cilia – Trap and move debris.

• Coughing and sneezing – Expel irritants.

• Epiglottis – Prevents food from entering the trachea.

DIGESTIVE SYSTEM

1. Functions of the Digestive System

• Ingestion – Bringing food into the body.

• Digestion – Breaking down food into smaller molecules.

  • Mechanical digestion – Chewing, churning, segmentation.

  • Chemical digestion – Enzymes and acids break down molecules.

• Absorption – Nutrients absorbed into blood or lymph.

• Defecation – Elimination of waste.

2. GI Tract Organs vs. Accessory Organs

• GI Tract Organs – Part of the digestive tube:

  • Mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus.

• Accessory Organs – Not part of the tube; secrete substances into it:

  • Salivary glands, liver, gallbladder, pancreas.

3. How Food Moves Through the GI Tract

• Ingestion → Mouth

• Mastication – Chewing (mechanical digestion).

• Peristalsis – Wave-like contractions that move food.

• Churning – Mixing of food with stomach juices.

• Segmentation – Back-and-forth mixing in the intestines.

• Defecation – Elimination of waste.

4. Layers of the GI Tract Wall

1. Mucosa – Inner layer; secretes mucus and enzymes.

2. Submucosa – Blood vessels, lymphatics, and nerves.

3. Muscularis propria – Muscle layer; controls peristalsis and segmentation.

   • Circular layer – Inner.

   • Longitudinal layer – Outer.

   • Oblique layer – Only in stomach.

4. Serosa – Slippery covering in the abdomen.

5. Adventitia – Anchors organs outside the abdominal cavity.

5. Stomach Secretions and Function

• Hydrochloric acid (HCl) – Kills bacteria and activates enzymes.

• Pepsin – Digests proteins.

• Mucus – Protects stomach lining.

• Gastrin – Hormone that regulates digestion.

6. Parts of the Small Intestine

1. Duodenum – Mixing station; receives bile and pancreatic enzymes.

2. Jejunum – Main site for nutrient absorption.

3. Ileum – Absorbs remaining nutrients; contains Peyer’s patches (immune function).

7. Structures That Increase Surface Area

• Plicae circulares – Circular folds.

• Villi – Finger-like projections.

• Microvilli – Brush border on epithelial cells.

8. Salivary Glands and Functions

• Parotid, sublingual, submandibular – Secrete saliva.

• Saliva:

  • Moistens food

  • Begins starch digestion (amylase)

  • Cleans mouth

  • Helps with taste

9. Pancreas Functions

• Exocrine:

  • Digestive enzymes

  • Bicarbonate (neutralizes acid)

• Endocrine:

  • Insulin and glucagon

10. Liver Functions

• Detoxifies blood

• Makes bile

• Stores glucose

• Makes plasma proteins

• Breaks down red blood cells

11. Bile

• Function: Emulsifies fats.

• Made in: Liver

• Stored in: Gallbladder

• Secreted into: Duodenum

12. Peritoneum and Mesenteries

• Peritoneum: Serous membrane around abdominal organs.

• Mesentery: Anchors intestines; contains blood vessels, lymphatics, and nerves.