Digestion Part 1 Flashcards
parts of alimentary canal (GI tract)
- mouth
- pharynx
- esophagus
- stomach
- small intestine
- large intestine
- digests and absorbs food
-accesory digestive organs=
teeth, tongue, gallbladder, salivary glands, liver, and pancreas
6 steps of ingestion
1. Ingestion Taking food in 2. Propulsion (peristalsis) Swallowing and peristalsis Wave contraction and relaxation of muscles in organ walls 3. Mechanical digestion Chewing, mixing, and churning food 4. Chemical digestion Catabolic breakdown 5. Absorption Move nutrients from Gi tract to venous blood/lymph 6. Defecation
is Chemical digestion catabolic or anabolic
Catabolic breakdown
Mechanical and chemical regulation of digestion
- Stretch receiptors
- Osmolarity
- Presence of substrate in the lumen
- nerve plexuses near GI tract initiate _______
- mediated by the gut
short reflexes
Extrinsic controls involve _______ and autonomic nerves
CNS
which reflex
- comes from within or outside GI tract
- involves CNS centeres and autonomic nerves
lng reflex
- serous membrane of abdominal cavity
Peritoneum
lines the body wall
Parietal peritoenum-
a mesentery has how many layers?
2
what does a mesentery do?
- Provides vascular and nerve supply to viscera
2. Holds digestive organs in place and stores fat
Retroperitoneal Structures
Kidneys and adrenals Bladder and urters Portions of duodenum Portions of colon Inferior vena cava Part of pancreas Aorta
Splanchnic circulation
blood flow to GI organs
-spleen, liver, and stomach, small and large intestines
Hepatic Portal Circulation:
- carries nutrient rich venous blood away from digestive organs
- delivers blood to liver for metabolic processing and storage
4 Tunic of GI tract
- Mucosa
- Submucosa
- Muscularis externa
- Serosa
Inner most layer/tunic
Moist epithelial
Lines lumens of GI tract
. Mucosa
what is the major functions of the mucosa layer of the GI tract?
Secretes mucus
Absorbs end products of digestions
Protects against infectious disease
what are the 3 sublayers of the mucosa layer?
- Epitelieul lining
- Lamina Propria
- Muscularis Mucoasae
- Has goblet cells- make mucus
- Eases food along GI tract
- Protects organs
Epiteliul lining of mucosa layret
- Loose areolar and reticular connective tissue
- Nourishes and absorbs nutrients
- Lymph nodes (defend against bacteria)
- Part of MALT (mucosa associated lymphatic tissue)
Lamina Propria of mucosa tunic
-Part of MALT (mucosa associated lymphatic tissue)
Lamina Propria of mucosa tunic
-Smooth muscle cells that produce local movement of mucosa
Muscularis Mucosae of mucosa layer
which stomach lining/tunic is
- dense connective tissue
- elastic fibers, blood/lymph vessels, lymph nodes, and nerves
submucosa
which GI tract tunic
- protective visceral peritoneum
- retroperitoneal organs and serosa
- smooth membrane, thin layer of cells
- excrete serous fluids
- fluid reduces friction with movement
serosa/serous membrane
-oral cavity-=
lips, cheeks, palate, tobuge
-gums, hard palate, and tongue are slightly ___________
keratinized
- plaatine bones and palatine process of the maxillae
- assits tongue in chewing
- slightly corrugated (Has grooves)
Hard palate
- mobile- skeletal muscles
- closses off the nasopharynx during swallowing
- uvula projects down from it
-soft palate
two plates of the skull that form the hard palate are not completely joined
cleft palate
complete vs incomplete palate
- complete cleft palate= soft and hard palate
- incomplete cleft palate= hole in the roof of the mouth (usually the soft palate)
functions of tongue
- Gripping and repositioning food during chewing
- Mixing food with saliva and forming the bolus
- Initiation of swallowing and speech
intrinsic or extrinsic muscles change the tongue shape
intrinsic
-extrinsic or intrinsic muscles alter tongue position
extrinsic
4 Papillae of tongue
Filliform
Fungiform
Circumvallate
Foliate
which papillae Provide roughness and friction
Cat tongue
No taste function
filliform
which papillae Scattered over tongue
Redish hue
Fungiform
which papillae form the V-shaped row on back of tongue
Circumvallate
which papillae are on the aide of the tongue
Foliate
groove on back of tongue
sulcus terinalis=
which tongue nerves sense pain
IX - in the back (9)
V- in the front (5)
which tongue nerves sense taste
- IX in the back (9)
- X in the back (10)
- VII in the front (7)
role of salivary glands
- clanse mouth
- moistena nd dissolvefood chemicals
- bolus formation
- enxymes to break down starch
_____ salivary glands- all over the mouth
-keep mouth moist
intrinsic
__________ salivaty glands (all have ducts and turn on and off)
-produce enzyme rich saliva
extrinsic
which salivary gland is
- anteroir to ear
- duct opens into vestibule
parotid gland
- below mandible
- duct opents at lingual frenulum
submandibular salivary gland
- under tongue
- opens via 10-12 ducts on floor of mouth
. Sublingual
-contests of saliva
Electrolytes
Digestive enzymes
Proteins
Metabolic waster
-exposed part above the surface of gum
crown of tooth
acellular and brittle part of tooth but hardest substance of body
-enamel-
part of tooth that is embedded in jawbone
-root=
_________ ligament- anchors tooth in the alveolus of jaw
-periodontal
the periodontal ligament -form the fibrous joint called a _________
gomphios
bonelike material deep to the enamel cap; bulk of tooth
dentin=
cavity surrounded by dentin
-pulp cavity=
part of tooth full of connective tissue, blood vessels, and nerves
-pulp=
portion of the pulp cavity extends to root of tooth
-root canal=
what cells secrete and maintain dentin during life
-odontoblasts=
-passage of food and fluids to esophagus
Pharynx
what is the pharynx lined with
stratified squamous epithelium and mucus glands
-muscular tube going from layrngopharyuns to stomach
Esohpagus
the esophagus goes through what structure?
-goes through diaphragm
protrusion of upper part of stomach into thorax through a tear or a weak diaphragm
-hiatal hernia=
sphincter moves above the diaphragm (slides)
-sliding vital hernia=
part of stomach herniates through without movement of the sphincter
-rolling hiatal hernia-
enzyme in saliva that breakdown starch/carbs in mouth
-amylase-
-chemical breakdown of protein starts in
stomach
Duglutition=
Swallowing
bucual phase of swallowing is voluntary or invoulnatary
=voluntary
pharyngeal phase of swallowing is voluntary or involuntary?
involuntary; controlled by medulla and lower pons
pylorus leads to the duodenum of SI via the ______sphincter
pyloric
additional oblique muscle layer of stomach that churns and pummels food
muscularis=
_______cells of stomach produce alkaline mucus
goblet
glands of the stomach
- mucous neck cells= secrete acid mucus
- parietal cells secrete HCL acid and intrinsic factor (for vitamin B12 absorption)
- chief cells= produce pepsinogen
- pepsingoen activated to pepsin by HCL in stomach and pesin itself via positive feedback
- enteroendorcine cells= secrete gastrin, histamine, endorphins, serotining, CCK
what gland of the stomach secrets secrete acid mucus
-mucous neck cells
what stomach gland secrete HCL acid and intrinsic factor (for vitamin B12 absorption)
parietal cells
-_____cells= produce pepsinogen
chief
____________ cells= secrete gastrin, histamine, endorphins, serotining, CCK
enteroendorcine
-horome that stimulates HCL production in stomach by parietal cells
Gastrin
-gastrin release stimulate by:
Stomach distensions
Vagal stimulation
Partially digested proteins in stomach
Hypercalcemia
-gastring release inhibited by:
Acid in stomach (negative feedback) Secretin GIP Glucagon Calcitonin
stomach lining mechanisms to protect against pathogens
- bicarbonate push mucus on stomach wall
- Tight junctions formed by epithelial cells
3, Gastric gland cells impermeable to HCL
-stomach secretes _________________- required for absorption of B12
intrinsic factor
Regulation of gastric secretions:
- Cephalic reflex (head)
- gastric phase
- intestinal phase
____________ reflex- regulates gastric emptying
-enterogastri
