Digestive System Flashcards
What is the alimentary tract ?
- tube extending from mouth to anus
- muscular tube lined internally by epithelium
What are the functions of the alimentary tract ?
- ingestion
- processing
- digestion
- absorption
- excretion
What is the journey through the alimentary tract ?
- food
- oral cavity
- pharynx
- epiglottis
- oesophagus
- stomach
- duodenum
- jejunum
- ileum
- caecum
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
- rectum
- anus
- faeces
What are the 4 abdominal quadrants and major organs in each ?
- RUQ - liver
- RLQ - caecum, appendix, intestine
- LUQ- stomach
- LLQ - intestine
What are the abdominal regions ?
- right hypochondriac region
- epigastric region
- left hypochondriac region
- right lumbar region
- umbilical region
- left lumbar region
- right iliac region
- hypogastric region
- left iliac region
What are the layers of the wall of the alimentary tract ? (Refer to pic)
- epithelium - inner most lining
- lamina propria
- muscularis mucosa
- submucosa
- circular muscle
- longitudinal muscle
- adventitia
- serosa
What is the role of epithelium in mucous membrane ?
- moistened by glandular secretions
- type of epithelium differed with tissue function
What is the lamina propria ?
- loose connective tissue
- small blood vessels, nerve fibres, lymphatic’s
- immune cells - e.g. macrophages + lymphocytes
What is the muscularis mucosa ?
- thin muscle layer
List the 3 layer of mucosa ?
- epithelium
- lamina propria
- muscularis mucosa
What is the submucosa ?
- 2nd layer of connective tissue, between mucosa + main muscle layers
- contains blood vessels, lymphatics, nerves
- Neural tissue - SUBMUCOSAL PLEXUS which regulates contractions & glandular secretions
What is the muscularis externa made of ?
- smooth muscle divided into 2 layers
- inner circular layer
- outer longitudinal layer
How are the layers of the muscularis externa arranged and what is their function?
- circular layer is a compact spiral + longitudinal is an elongated helix
- layers orientate in different directions
- contractions propel materials along tract
What is the myenteric plexus and where is it located ?
- 2nd nerve muscle plexus located between muscle layers of the muscularis external
What is the myentric plexus and where is it located ?
- 2nd nerve muscle plexus located between muscle layers of the muscularis external
What covers the outside of the muscularis externa?
- adventitia and/or serosa
- Alimentary canal suspended in peritoneal cavity, covered in SEROSA
What is the difference between serosa + adventitia ?
- serosa covers organs in the peritoneal cavity, allowing movement
- retroperitoneal organs are covered in adventitia, but not serosa, and adventitia helps hold organ structures together.
What lines the oral cavity + what are it’s functions ?
- lined by stratified squamous epithelium
• Ingestion and fragmentation of food
Where are the small salivary glands located ?
- in submucosa of oral cavity and tongue
What are 3 main groups of large salivary glands ?
- Sublingual: beneath tongue, many ducts
- Submandibular: floor of mouth, inner surface of mandible, ducts behind teeth
- Parotid : Largest, empties at the 2nd Molar (gets inflamed if you have mumps)
What is oral drug administration ?
- Given by mouth and swallowed
• Easiest and safest method, but slow absorption
What is sublingual administration + limitation ?
- placed under the tongue – dissolves in saliva
• Rapid absorption, higher circulating levels
• limitation = not for bad-tasting or irritating medications
What is buccal drug administrations + disadvantage ?
- Placed in mouth next to cheek (tablet form)
• Rapid absorption, higher circulating levels
• Disadvantage -Possibility of swallowing the pill
How long is the oesophagus + where does it pass through ?
- 25cm long, through diaphragm to stomach
- contracts rhythmically toward stomach