Digestive System Flashcards
1
Q
How are the digestive system organs divided?
A
- Alimentary canal: GI tract/gut
o Muscular tube from mouth to anus
o Digests and absorbs food - Accessory Digestive Organs
o Produce secretions to digest food
o Teeth, tongue, salivary glands, gallbladder, liver, pancreas
2
Q
What happens/where during the digestive process?
A
- Ingestion + propulsion –> mechanical breakdown –> chemical digestion –> absorption –> defecation
3
Q
Explain each digestive process
A
- Propulsion
o Swallowing
o Peristalsis – involuntary; contraction/relaxation of organ walls - Mechanical breakdown
o Chewing
o Mixing
o Churning
o Segmentation – constriction of small intestine + digestive juices - Chemical Digestion – breakdown into chemical blocks with enzymes
- Absorption – end products (vitamins, minerals, and water) from lumen through mucosal cells into blood or lymph
- Defecation – get rid of indigestible solid wastes
4
Q
What controls digestive activity? What do the receptors respond to?
A
via mechano and chemoreceptors
- Mechano and chemoreceptors respond to:
o Stretching of organ from food
o Presence of substrates and end products
o Osmolarity
o pH - receptors initiate reflexes that:
o activate or inhibit glands
o stim smooth muscle to mix contents and move them
5
Q
What relationship does the GI have with the Peritoneum?
A
- Peritoneum – serous membrane of ab cavity
o Visceral – external of digestive organs
o Parietal – lines entire body wall - Peritoneal cavity – fluid filled space between the two
o Lubes - Mesentery – double layer of Peritoneum
o Extends organs from body wall
o Vascular and nerve supplier to visceral
o Holds organs in place
o Stores fat - Peritoneal Organs – surrounded by peritoneum: stomach
- Retroperitoneal organs – outside the peritoneum: pancreas, duodenum, large intestine
6
Q
What provides blood to the digestive system?
A
- Splanchnic Circulation – arteries branch off aorta to serve digestive organs
o Celiac trunk branches supply stomach and liver
o Mesenteric arteries – supply small and large intestines - Hepatic portal
o Collects nutrient rich venous blood from: stomach, small/large intestines –> liver for metabolic processing and storage via hepatic portal vein
7
Q
What are the 4 layers of the alimentary canal?
A
- Mucosa
o Secretes mucous, digestive enzymes, absorbs end products into blood, protects bad bacteria - Submucosa
o Supply blood vessels and nerve fibers - Muscularis externa
o Smooth muscle = segmentation and peristalsis (sphincters) - Serosa
o Holds everything together; visceral peritoneum
8
Q
What structures make up the oral cavity?
A
- Buccal cavity – stratified squamous epithelium with keratinization for protection
- Teeth – mastication
- Palate –
o hard palate – anterior; rigid bone for chewing
o soft palate – posterior; skeletal muscles closing nasopharynx during swallowing + uvula - tongue – skeletal muscle
o mixes food with saliva to compact mass (Bolus)
o papillae either contain taste buds or provide friction
9
Q
What are the different salivary glands?
A
- Major salivary glands – produce most saliva presence of food and though of food
o Parotid glands
Mumps – inflammation caused by virus and common in childhood
o Submandibular glands
o Sublingual glands - Within glands, saliva is secreted from?
o Serous cells – watery secretion with enzymes
o Mucous – mucus
10
Q
What is the purpose of saliva and what is it made up of?
A
- Functions
o Cleaning
o Dissolve foods
o Moisten food into bolus
o Contain enzymes for chemical breakdown of starch - What is it made of?
o Electrolytes
o Digestive enzymes:
Salivary amylase – breaks down starch
Lingual lipase – breaks lipids
o Protein: mucin, lysosome, defensin, lgA
11
Q
What makes up the Pharynx?
A
- Throat
- Oropharynx –> laryngopharynx
- Squamous epithelium and mucus
- Two skeletal muscles – propel food into esophagus
12
Q
What makes up the esophagus?
A
- Muscular tube from laryngopharynx to stomach
o Change from skeletal to smooth - Upper esophageal sphincter gastroesophageal sphincter
- Joins stomach at cardiac orifice
- What does mucus do?
o In gastroesophageal sphincter protects esophagus from reflux of stomach acid
13
Q
What happens during Deglutition (swallowing)?
A
- Highly coordinated with tongue + soft palate + etc
- Buccal Phase
o Mouth and voluntary
o Tongue pressed against roof, bolus is forced into oropharynx
o Swallowing past uvula is involuntary - Pharyngeal-esophageal phase
o Involuntary
o All routes sealed except digestive tract
o Peristalsis moves food
14
Q
What digestive processes are the Mouth and its accessory organs involved in?
A
- Ingestion
- Mechanical breakdown
- Chemical digestion
- Propulsion
15
Q
What is the stomach and what occurs there?
A
- Smooth muscle storage tank
- Chemical breakdown of proteins + food converted chyme
- 50ml when empty or 4L when full
- Vomiting (emesis) – stretching or irritant
- Collapses into folds when empty (rugae) – sound
16
Q
What structures exist within the stomach?
A
- Cardia – opening
- Fundus – dome at top
- Body – midportion
- Pyloric part – distal region
o Pyloric antrum + canal - Pyloric sphincter – end duodenum
