Wray- Digestive System Flashcards
Mouth/ Oral Cavity
If it is cut, mucosa cells produce antimicrobial peptides to protect against infection
Uvula (3)
- Conical structure in the back of the throat
- Prevent food going down through the breathing passage while you swallow
- Involved in speech
Tongue (3)
- Made of skeletal muscle
- Mixes food with saliva to create a compact ball of food
- Initiates swallowing
Salivary Glands (4)
- Clean and moisten mouth and food
- Contain enzyme Amylase –> Breaks down carbohydrates
Teeth: External (3)
- Crown: visible portion of teeth above gum line
- Neck: Area where the crown joins the root
- Root: Portion of teeth embedded in the jaw
- 1-3 roots
Teeth: Internal (3)
- Enamel:
- Dentin:
- Pulp Cavity
Dental Disease: Dental Plaques
A film of sugar and bacteria that adhere to the teeth
Dental disease: Cavities
Demineralization of enamel and dentin by bacterial
Dental disease: Gingivitis
Result of unremoved plaque that could disrupt the seal between teeth and gum allowing bacteria to infect the gum
Pharynx:
Throat
- Similar histology to mouth
Esophagus
- Muscular tube about 25 cm
- Connect mouth to stomach
- Epiglottis: closes the larynx when food passes through pharynx
Gastroespohageal sphincter:
- Muscle that controls food entry to stomach
- Prevent gastric juices to back into the esophagus
Stomach: location
- left quadrant of abdominal cavity
- underneath the cavity
Stomach: function
- temporary food storage
- Initial breakdown of proteins and lipids
- Produce chyme (creamy paste)
Stomach: size
- empty 50 mL
- Full 4L
- Rugae: fold in the stomach wall that allows the stomach size to increase
Acidic environment of stomach
- HCl
- 100,000 x more acidic than blood (2 –> 7)
Protection: - Alkaline (basic) mucous layer that protects cells
- Fast replacement of cells
Digestive process in stomach
- Protein digestion starts by HCl and pepsin
- Lipid digestion is initiated by lipase
Can we survive without a stomach?
YES
Gastric Ulcer (3)
- Erosions on the stomach wall
- Bacteria with a drill-like head to breach/destroy the mucosal layer
- Healing ulcers: antibiotics
Small Intestine: Pyloric sphincter
- Controls how much food enters the SI
Small Intestine Function
Digestion of food and absorption of nutrients
Small Intestine: Duodenum
- 25 cm
- Bile duct ends there delivering bile from the liver
- Pancreatic duct ends there delivering pancreatic juices
- Digestion and absorption of all nutrients is either initiated of continues
- Most important portion of the SI
Small Intestine: Jejunum
2.5 m (8 ft): Food/nutrient absorption
Small Intestine: Ileum
- 3.6 m (10 ft): Nutrients absorption
Large Intestine: Function (3)
- Water reabsorption
- Removal of waste
- Breakdown of fiber (indigestible carbs)
Large Intestine: Components
- Cecum
- Colon
- Rectum
- Anal canal
- Anus
Large Intestine: Cecum
- first part of LI
- connects SI to ascending colon
Large Intestine: Colon Function (3)
- Move waste products out of the body
- Absorb water
- Break down fiber
Large Intestine: Colon Parts (3)
- Ascending colon
- Transverse colon
- Descending colon
Large Intestine: Rectum
- Final portion of LI
- Storage of feces
Accessory organs of digestive system (3)
- Liver
- Gall bladder
- Pancreas
Liver: function
- Filter and process nutrient rich blood delivered from GI tract
- Secrete bile essential for food digestion
- Packs and stores extra nutrients received from SI
Liver: Location
- Top right of abdominal cavity
- underneath diaphragm
- Largest organ
Bile
Emulsification of fat
- Lipase digests fats
- Bile breaks down fats into smaller pieces to aid lipase in the complete breakdown (increases surface area)
Liver lobes
- Large right
- Small left
Liver: Hepatocytes
- Liver cells
- Secrete bile essential for food digestion in SI
- Detoxification of blood ammonia –> Urea
Liver: Blood vessels (3)
- Hepatic portal vein
- Hepatic artery
- Central vein
Liver: Hepatic portal vein
- brings blood from digestive tract
2. nutrient rich blood from the GI tract must pass through liver to detoxify
Liver: Hepatic artery
Bring oxygenated blood from the heart
Liver: Central vein
- Takes deoxygenated blood back to the heart
- Combination of blood from hepatic artery and hepatic portal vein
- Connects to the IVC
Hepatitis: definition
inflammation of liver due to viral infection
_______ Hepatitis viruses have been identified:
Six (A - F)
HVB & HVC
transmitted via blood –> causes chronic hepatitis and liver cirrhosis
Cirrhosis:
- Damage to the hepatocytes
- Causes blockage of hepatic portal
Gallbladder: Location
green muscular sac located inferior to liver
Gallblader: Function
Stores concetrated bile that is not immediately needed
Pancreas: Location
Tadpole-shaped organ that sits inferior to the stomach
Pancreas: Function
Produces enzymes (pancreatic juices) that breaks down all food groups
Pancreatic juices: (4)
- Trypsin
- Amylase
- Lipases
- Nucleases
Trypsin
Breaks down proteins
Amylase:
Breaks down carbohydrates
Lipases:
Breaks down fats that have been emulsified by bile salt
Nucleases:
breaks down nucleotides
How much time does the food spend in the small intestine
3-6 hours
Small intestine absorbs
AA, sugars, fatty acids, toxins, and medications
- Sends it to the liver –> detoxifies –> heart