abdomen Flashcards

Question

Tongue

Answer 1

Accessory digestive organ composed of skeletal muscle held together by connective tissue Gustation (taste) is detected by most papillae found on the tongue - Foliate papillae (most) - Fungiform papillae (most) - Circumvallate papillae (all) (vallate papillae) - Filiform papillae (none) Filiform papillae increase friction between the tongue and food to aid propulsion

Answer 2

Functions: - Chemical breakdown - Propulsion (aids with) 3 pairs of glands: - Parotid (Stenson’s duct) - Submandibular (Wharton’s duct) - Sublingual (Lesser sublingual ducts) Salivary glands are composed of ‘racemose glands’ which consist of large lobules, in which there is: - Mucous alveoli - Serous alveoli (ptyalin)

Answer 3

- Muscular tube forming the digestive and respiratory system - The nasopharynx is occluded when swallowing - Larger amounts of lymphoid follicles exist in the tonsils (adenoids) to defend against pathogens like bacteria. Walls of the pharynx: - Mucous coat Nasopharynx – ciliated epithelium oro- & laryngopharynx – stratified epithelium - Fibrous coat – thickest layer and encapsulates the tonsils - Muscular coat – contains 3 constrictor muscles: Superior, Middle and InferiorThese muscles contract to swallow

Answer 4

There are 3 natural narrowings of the oesophagus: - At its commencement - Level of the left main bronchus - Level it passes through the diaphragm "oesophageal hiatus" It is approximately 25 cms long Structure of the oesophageal wall: - Outer coat of areolar tissue - Muscular coat of muscle fibres - Submucous coat of loose areolar tissue - Inner mucous coat of stratified squamous epithelium

Answer 5

The contraction and relaxation of muscle layers in the alimentary tract - It occurs in waves, which push the contents of the tract onwards - This process is under the influence of sympathetic and parasympathetic nerves

Answer 6

The stomach is a J-shaped portion of the GIT, located in the left upper quadrant of the abdominal cavity (Waugh and Grant 2014). Anatomical regions include: - Cardia - Fundus - Body - Pylorus - It is a reservoir for food and liquids - Produces gastric juices (containing HCL, pepsin intrinsic factor and gastric lipase) Functions: - Mechanical breakdown – due to the three layers of muscle fibresPeristaltic waves mix food with gastric juice and propel it into the duodenum - Digestion – Enzymes like pepsin begin to breakdown proteins - Absorption – absorbs a few fat-soluble substances (aspirin, alcohol, some drugs) The mucous membrane forms longitudinal folds when the stomach is empty (Rugal folds/Rugae of mucosa) The three muscular layers allow for multidirectional compressions to ‘churn’ food, resulting in “Chyme”

Answer 7

Lining consists of columnar epithelial cells: - Cardiac glands: near the cardiac orifice and mainly secrete mucus - Gastric glands: in the fundus and body which secrete gastric juice - Pyloric glands: in the pyloric antrum and secrete mainly mucus - In the gastric pits, the gastric glands (Parietal and chief cells) produce ‘gastric juice’ - There is a limited amount of absorption in the stomach but there is a lot of preparation for it

Answer 8

The liver, gallbladder and pancreas connect to the alimentary tract via the common bile duct and enter the duodenum through: The ampulla of Vater (common duct) The sphincter of Oddi (muscular sphincter) Out through the opening called the major duodenal papilla These are accessory digestive organs The pancreas is about 12-15 cm long with lobulated texture It consists of a broad head, long body and narrow tail The liver is the largest gland in the body, weighs around 1.5kg Divides into four lobes: Large left, large right, caudate and quadrate The falciform ligament divides the left and right lobes The gall bladder is a pear-shaped sac that is approximately 10cm long and hangs inferiorly from the liver

Answer 9

Pancreas – Islets of Langerhans: A-Cells release glucagon B-Cells release insulin D-Cells release somatostatin Liver: Receives two blood supplies Hepatic artery (Oxygenated) Hepatic portal vein (absorbed nutrients) Secretes bile Gallbladder Stores bile secreted from the liver

Answer 10

Functions: Mechanical breakdown – Segmentation and peristalsis Digestion - digestive enzymes delivered from pancreas and brush border enzymes attached to microvilli membranes complete digestion of all classes of foods Absorption – Broken down products e.g. carbohydrates, proteins, fats, vitamins, electrolytes, water It is sub-divided into 3 sections: Duodenum approximately 25 cm long 4 parts D1, D2, D3 and D4 D2 – site of the Major papilla/Ampulla of Vater/Sphincter of Oddi Jejunum approximately 2 metres long Ileum approximately 3 metres long Ends at the ileo-caecal valve – this valve prevents backflow Unlike the stomach the folds do not smooth out when distended

Answer 11

Villi are tiny finger-like projections, covered by simple columnar epithelial cells (enterocytes) which is ‘carpeted’ by microvilli. Along with blood vessels it contains a lymphatic vessel (lacteal) to transport material that cannot cross capillary walls (Waugh and Grant 2014). At the base of the villi are the entrances to intestinal glands that secrete a watery intestinal juice. The intestinal glands also contain endocrine cells that secrete intestinal hormones (Martini, Bartholomew and Bledsoe 2007).

Answer 12

Segmentation is rhythmic local constrictions of the small intestine, mixing food with digestive juices and making absorption more efficient by repeatedly moving different parts of food mass over the intestinal wall (Marieb and Hoehn, 2013).

Answer 13

Segmentation is rhythmic local constrictions of the small intestine, mixing food with digestive juices and making absorption more efficient by repeatedly moving different parts of food mass over the intestinal wall (Marieb and Hoehn, 2013).

Answer 14

Approximately 1.5 metres long The first section: The CaecumIt is a dilated region with a blind end inferiorly connecting to the appendix The colon has four main parts, which have the same structure and functions. They are: The ascending colon that passes upwards from the caecum to the level of the liver where it curves to the left at hepatic flexure. The transverse colon that extends across the abdomen to the area of the spleen where it curves inferiorly at the splenic flexure. The descending colon that passes down the left side of the abdomen. The sigmoid, which has an S-shaped curve in the pelvic cavity.

Answer 15

Functions: Digestion – some remaining food residues are digested by gut bacteria (which also produce some vitamin K and some B vitamins) Absorption – absorbs most remaining water, electrolytes (largely NaCl), vitamins produced by bacteria and some drugs Propulsion – peristaltic waves propels faeces toward rectum by mass movements Storage – Faeces accumulates until it is expelled from the body Defecation – reflex triggered by rectal distension; eliminates faeces from body Mass peristalsis is a strong wave propelling faeces along the transverse colon into the descendingIt usually occurs at intervals roughly twice an hour or when food enters the stomach

Answer 16

Blind ended tube Approximately 8-10 centimetres It shares the same wall structure as the large colon but has more lymphoid tissue. No digestive function Positions can vary Clinical context: Appendicitis is inflammation caused by an obstruction of the lumen

Answer 17

The rectum is a slightly dilated portion of the large intestine measuring about 13 cms long The anal canal is a short passage that opens exteriorly form the body Usually the rectum is empty, but when a mass movement pushes the contents from the sigmoid into the rectum, the nerve endings in its walls are stimulated by stretching leading to defecation It is under control of two sphincters: The internal sphincter consists of smooth muscles and under control of the autonomic nervous system The external sphincter consists of skeletal muscle and is controlled voluntarily

Answer 18

There are 9 abdominal regions 6 main functions Ingestion, propulsion, mechanical breakdown, chemical digestion, absorption and defecation 4 layers of the alimentary tract wall Mucosa, submucosa, muscularis and serosa There are two groups of organs that form the digestive system Gastrointestinal tract (Alimentary tract) Accessory digestive organs