DIGESTIVE SYSTEM Flashcards
what would happen if saliva was not produced
- would be very hard/ impossible to swallow
- starch would not be converted into maltose
- bad oral hygiene
- no lysozyme
- would be hard to taste
- no food dissolved
define gingivitis
inflammation of the gums
define halitosis
bad breath
state the location and function of the epiglottis
leaf shaped flap of cartilage located behind the tongue at the top of the larynx
main function is to seal the trachea during eating so that food isn’t inhaled
define dysphagia
difficulty swallowing
name the exit and entry structures of the stomach
- bolus enters the stomach through the lower esophageal sphincter
- chyme exits the stomach through the pyloric sphincter
state the major function of the stomach
- secrets acid and enzymes that digest food
- acts as a temporary storage tank
- compresses, kneads and mixes food with gastric juices to become chyme
state the function of intestinal juices
hydrochloric acid (HCI)- kills microbes H+ ions are actively pumped into the lumen by proton pumps
mucus- protects stomach wall from being damaged by the HCI
gastric enzymes- pepsin begins the chemical digestion of proteins
state the pH level of the stomach and explain why it should be this level
pH-2 needs to be acidic enough to kill bacteria
describe the homeostatic imbalance that can occur with prolonged or severe vomiting
excess vomiting can cause dehydration and disrupt the electrolyte and pH balance
As acid is lost the blood becomes more alkaline
what are the 6 digestive processes
- ingestion
- motility
- secretion
- digestion
- absorption
- secretion
describe ingestion
taking food into the mouth, chewing and swallowing
describe digestion
the breakdown of large insoluble molecules into small soluble ones through both chemical and mechanical digestion
describe motility
movement by the muscularis component of the digestive tube, including mechanical digestion e.g. peristalsis and segmentation
describe secretion (digestive process)
release of digestive juices that facilitates digestion. some digestive organs secrete endocrine hormones to regulate digestion or metabolism of nutrients
describe absorption (digestive process)
movement of digestive nutrients through GI mucosa and into the internal environment
describe elimination (digestive process)
excretion of residues of the digestive system (feces) from the rectum, through the anus, defecation
name the 4 layers of the digestive tract in the correct sequence from inner-most to outer layer
- mucosa
- submucosa
- muscularis
- serosa
describe mucosa layer
innermost layer of the digestive tract facing the lumen of the tube. function is to secrete mucus, digestive enzymes and hormones. absorbs products of digestion and protects against disease
describe the submucosa layer
areolar connective tissue layer that binds mucosa to muscularis, contains blood and lymphatic vessels to receive absorbed nutrients and nerves to control the gi tract.
forms the submucosal plexus
function to regulate digestive tract movement/ secretion
state two situations that impact on the functioning of the defecation reflex
- diarrhoea
2. spinal injury
describe the defecation reflex using components of the reflex arc
stimulus: initiated when rectum is distended
control center: in the sacral spinal cord
action of effector: lower colon and rectal wall contracts internal and sphincter relaxes
aided by voluntary contraction of diaphragm and abdominal muscles and relaxation of external anal sphincter
name the main nerve involved in regulating the digestive system
vagus nerve
what is the autonomic nervous system that stimulates the digestive system
parasympathetic nervous system
what is the gastroileal reflex
stomach descends and stimulates peristalsis in the small intestine which delivers that content to cecum
what is the gastrocolic reflex
stimulates mass peristalsis in colon which is initiated when the stomach is descended
describe the mechanical movements of the small intestine
peristalsis: sequencinal contraction and relaxation of smooth muscle to propel chyme through digestive tract
segmentation: contraction of alternating sections of the small intestine to mix chyme and maximise digestion and absorption
name the 4 structural features of the small intestine and state the overall function of these features
circular folds: 1cm deep folds force chyme to spiral through the lumen, slow its movement and allowing more time for absorption
villi: finger like projections of the mucosa which contain blood capillaries and lacteals (for fat absorption)
microvilli: tiny projections of plasma membrane of the cells surface of villi for secretion of intestinal enzyme and absorption
name the 3 sections of the small intestine in order
- duodenum
- jejunum
- ileum
describe the 2 functions of the small intestine
- absorption
2. secretion of enzymes
describe the major nursing consideration relating to the dysfunction (or disease) of the small intestine
peptic ulcers
dehydration/ malnutrition due to lack of absorption of nutrients
weight loss
low appetite
state function of intestinal juice
contains hormones, digestive enzymes, mucus, substances to neutralize HCL from stomach and pepsin
which digests polypeptides into amino acids
describe the order of the large intestine
chyme enters via the ileocecal sphincter
- cecum
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
- rectum
- anus
state the 4 functions of the large intestine
1: absorption of water, ions and vitamins
2. movement of contents of colon to rectum
3. production of vitamin k and some b vitamins by bacteria
4. formation of feces and defecation
describe the mechanical movements of the large intestine
- peristalsis
- haustral churning, relaxed pouches are filled and then contracted to move chyme to next haustra
- mass peristalsis, strong peristalsis strong peristaltic waves beginning in the mid transverse colon to quickly move the contants towards the recum
describe the location of the appendix
RLQ/ right iliac region
health risks associated with tooth and gum disease
cavaties
plaque
gums become red, sore swollen and bleed
causes chronic inflammation which increases risk of heart disease and stroke
state 2 functions of the tongue
- chewing food into smaller pieces making them easier to digest
- releases saliva which contains enzymes that help break up food
state 2 functions of saliva
softens moistens and dissolves food
cleans mouth and teeth
2 situations that would reduce production of saliva
- dehydration
2. side effects of medication
what are 4 contents of saliva and functions of each
water; dissolves food to begin the digestive process and stimulates taste buds
salivary amylase: digests starch to maltose
mucus: lubricates food for movement and swallowing
lysozyme: helps destroy bacteria
describe the anatomical position of the liver
occupies most of the right hypochondriac and epigastric region
posterior to the ribs
left lobe is in the left hypochondriac region
state the 7 functions for the liver
- bile production
- phagocytosis
- processing nutrients
- storage
- formation of blood components
- detoxification of alcohol and drugs
- heat production
state the function of the stellate reticuloendothelial (kupffer’s) cells
forms part of the sinusoid walls and are hepatic macrophages which remove debris like bacteria and worn out blood cells from the blood as it flows past
name the functional cells of the liver and describe what they do
- hepatocytes are liver cells which are arranged in rows
- hepatocytes contains large amounts of RER, SER, golgi complexes and mitochondria
- the hepatocytes produce 500-1000mls bile/day
name the cells that produce bile
hepatocytes produce bile when there is fatty chyme in the GI tract
describe the pathway of bile from the liver to the duodenum
right/ left hepatic duct common hepatic duct cystic duct from gallbladder common bile duct pancreatic duct from pancreas
name the structures that store bile
gallbladder
describe the main function of bile
- neutralise acid from the stomach
- emulsification of fat to enable digestion and absorption of lipids
- removal of waste (bilirubin)
what are the contents of bile
pH 7.6 to 8.6 alkaline
H2)
bicarbonate ions (HCO3) to help neutralise the acid from the stomach
bile salts which emulsify fats, bile pigments waste production
describe the anatomical position of the pancreas
located posterior to the stomach in the epigastric region
function of the pancreas
produce pancreatic juice which flow down the pancreatic duct into the duodenum with bile from the common bile ducts
describe the muscularis layer
an inner circular and outer longitudinal layer of smooth muscle
function: mixing and peristalsis of contents of the lumen
describe serosa
made up of serous membrane that lines abdominopelvic cavity and covers its organs
serosa is the visceral layer of the peritoneum
function: allows movement of organs inside the abdominal cavity without friction
name the 3 layers of the peritoneum in the correct sequence deep to superficial
- visceral covers organs - deepest layer
- peritoneal cavity - serous fluid
- peritoneal layer- most superficial layer
state 4 functions of the tongue
- taste
- manipulation of food for chewing
- aids swallowing
- articulates speech
describe 5 effects of aging on the GI tract
- decreased gustation and olfaction impact on pressure associated with eating
- altered dental function decreased ability to chew and bite
- decreased secretion of digestive enzymes limits digestive function
- decreased motility/loss of smooth muscle tone
- decreased neural and hormonal control
describe the blood flow around the liver
blood enters the liver from the hepatic artery (oxygenated) hepatic portal vein (deoxygenated but nutrient rich blood into the liver from stomach. spleen and intestine)
these flow through sinusoids and central veins in each liver lobule
hepatic vein leaves liver and takes blood to inferior vena cava
