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DIGESTIVE SYSTEM

DIGESTIVE SYSTEM. Introduction. concerned with the function of nutrition which includes ingestion, digestion, absorption and egestion process of digestion involves the physical and chemical breakdown of food to render it soluble and ready for reabsorption

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DIGESTIVE SYSTEM

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  1. DIGESTIVE SYSTEM

  2. Introduction • concerned with the function of nutrition which includes ingestion, digestion, absorption and egestion • process of digestion involves the physical and chemical breakdown of food to render it soluble and ready for reabsorption • tongue and teeth help in mechanical breakdown of food • chemical digestion occurs with help of digestive juices containing enzymes secreted by the digestive glands • secretion of enzymes is basically under the control of hormones • passage of food along the digestive tract is aided by gut motility controlled by nervous system

  3. Incomplete Type • when anus is absent, mouth serves for ingestion of food and egestion of waste materials Fasciola or Clonorchis Parts: • mouth – anterior end • oral sucker – circular and muscular sucking disc surrounding the mouth • pharynx – short muscle • esophagus – short tube from the pharynx additional for Fasciola • side branches or diverticula of the intestines are very prominent and seem to fill the body

  4. COMPLETE TYPE • mouth and anus are present • may be subdivided into the digestive tract, the digestive glands, and the accessory structures

  5. Coelom, Peritoneum, and Mesenteries Coelom • – cavity containg the visceral organs divided into: a. small pericardial cavity – contains the heart b. larger pleuro-peritoneal cavity – which contains the rest of the visceral organs Peritoneum – connective tissue membrane that lines the coelom Types: a. parietal peritoneum – lines the body wall b. visceral peritoneum – covers most visceral organs

  6. Coelom, Peritoneum, and Mesenteries Mesenteries • two layers of the peritoneum that suspends viscera from the dorsal body wall • name of organ they suspend Omentum • double membrane continuous with the mesenteries that connect the visceral organs with one another • also named after organ they connect

  7. Buccal Cavity • large cavity exposed upon opening the mouth Parts: • maxillary teeth – in the upper jaw • sticky tongue – located at the floor of the cavity which captures food and passes it on the esophageal opening • glottis – slit-like opening to the respiratory system and is found at the region between the tongue and esophageal opening • vocal sacs – where pair of slits lead to ; slits are located lateral to the glottis and near angle of jaw • choanae or internal nares- pair of holes at the roof of the buccal cavity • vomerine teeth- pair of v-shaped formations at the root of the mouth • Eustachian tube – opening or recess near the angle

  8. 4 • Vomerine Teeth • Internal Nares 3. Opening to the Eustachian Tube 4. Maxillary Teeth

  9. Digestive Tube • esophagus – short tube connecting the oral cavity to the stomach 2. Stomach – bag shaped muscle Parts of stomach: a. cardiac end – anterior portion continuous with the esophagus b. pyloric end – posterior portion continuous with the small intestine c. greater curvature – outer curvature d. lesser curvature – inner curvature e. rugae – lines of the inner wall of the stomach 3. pyloric sphincter – constriction at the junction of the stomach and the small intestine

  10. Digestive Tube 4. Small Intestine - digestive tube that has become the long coiled structure from the pylorus - where most chemical digestion and absorption occurs Has 2 regions: a. duodenum – bends anteriorly from the pylorus and runs parallel to the stomach b. ileum – longer and posterior 5. Large Intestine - where digestive tube enlarges - further breakdown of undigested material by bacterial action and the absorption of water occur here

  11. Digestive Tube 6. Cloaca – short narrow tube which opens to the outside through the anus - urine and gametes also pass through the cloaca and anus Mesenteries found in digestive system • dorsal mesentery – digestive tube is suspended from the dorsal body • mesogaster – mesenteries in the stomach at its cardiac end • mesentery proper or mesenterium – suspends the ileum • mesorectum – suspends rectum • Spleen – dark lymphoid organ lying within the fold of the mesorectum

  12. Parts of the Digestive System 3. Spleen 4. Liver 5. Stomach 6. Small Intestine 7. Large Intestine

  13. RESPIRATORY SYSTEM

  14. Types of Respiratory Organs 1. gills - aquatic animals 2. lungs – evaginations (outpocketings )of the digestive tube for terrestrial animals 3. tracheal system – invaginations of the integument (inpocketings)

  15. TYPES OF RESPIRATORY SYSTEM

  16. AQUATIC RESPIRATORY SYSTEMS Gills of Fishes -are delicate comb-like structures a. Operculum – covers the gills b. Gill chamber – part of the pharynx c. Gill arches – bony structures where gills are arched d. Gill filaments – arranged in parallel rows in rich in blood capillaries, this also gives the dark red color of the gills in live or fresh specimen e. Pharyngeal clefts- wide slits between the gill arches which serve for the passage of water from the pharynx to the gill chamber Breathing Movements of Fishes • water is taken in through the mouth and made to pass through the gills then expelled out of the gill chamber through the gill aperture

  17. TERRESTIAL RESPIRATORY SYSTEMS Tracheal System of Insects • respiratory organs consists of a branching system of air tubes which supplies oxygen directly to the tissues Parts • tracheal trunk – short segmental branches that lead outside to spiracles and in fine branches, the tracheoles, connected directly to the tissues • spiracles – where exchange of gases occur

  18. TERRESTIAL RESPIRATORY SYSTEMS Lung System of Vertebrates Parts • glottis – median slit, posterior to the tongue which leads to the larynx • arytenoids – pair of cartilages on both sides of the glottis which is covered by mucous • cricoid cartilage – ring shaped cartilage that borders arytenoids • vocal cords – a pair of elastic, thread-like bands • lungs – pair of spongy sacs where larynx leads to

  19. Excretory System

  20. Frog’s Excretory System Kidney • flat, ovoid reddish organs lying in a space • retroperitoneal • adrenals maybe observed as the yellowish streaks on the ventral surface Cisterna Magna • space between the muscles of the dorsal body wall and the peritoneum Mesonephric or Wollfian Duct • thread like tubular structure on the lateral side of each kidney • continues posteriorly beyond the kidney and enters the cloaca separately on its dorsal wall Urinary Bladder • connected to the ventral wall of the cloaca which serves as storage of urine

  21. Parts of the Excretory System 8. Kidney 9. Urinary Bladder

  22. Mammalian Kidney Kidney substance is easily divisible into two regions: • outer cortex - contains the microscopic renal corpuscles and tubules • inner medulla - contains collecting tubules that open at the renal papilla Renal Pelvis - where renal papilla opens - expanded beginning in the ureter or metanephric duct Metanephric Duct – leads tourinary bladder Ureter – closely associated with blood vessels • * all are found in a concavity called the hilus

  23. CIRCULATORY SYSTEM

  24. Function of the Circulatory System • Responsible for the transport of gases, nutrients, metabolic wastes, hormones and other substances in the different parts of the body. • It assists in maintaining constancy of the internal environment (homeostasis) of the organism

  25. OPEN SYSTEM • Heart • Pericardial sinus  cavity where the heart lies; open at the posterior end • Dorsal Diaphragm  membrane forming the ventral wall of the pericardial sinus • Aorta  vessel from the anterior end of the heart, which opens into the sinuses of the head • Composed of a series of chambers • Ostia: paired lateral openings at the posterior end of each chamber which are guarded by valves

  26. Path of Blood • Colorless blood from the pericardial sinus enters each chamber thru these openings. • Blood is kept in circulation by the rhythmic contraction of the chambers of the heart from the posterior to the anterior chambers of the aorta • Blood then permeates into the different parts of the body and finally returns to the pericardial sinus through the posterior opening.

  27. CLOSED SYSTEM Blood Vascular System Composed of: a. Blood b. Heart - pumping action of the heart creates pressure that drives - the blood to the different parts of the body c. Arteries - conveys blood from the heart to the different parts of the body d. Veins - convey blood back to the heart e. Capillaries - connect arterioles with the venules Arterioles  small arteries Venules  small veins

  28. Lymphatic System Composed of: • Lymph vessels • Lymph spaces • Lymph  circulating fluid Where is it located? Dorso-lateral subcutaneous connective tissue  Tissue connecting the skin to the body wall Dorsal subcutaneous lymph space  space between the skin and the dorsal body wall  where lymph is pumped into veins by lymph hearts Lymph Hearts  Contractile hearts found between the third vertebra and the posterior corners of the suprascapula Anterior Abdominal Vein  underneath the linea alba

  29. HEART a. Pericardial cavity  where the heart lies  separated from the pleuroperitoneal cavity by the transverse septum b. Parietal pericardium (pericardial sac)  lining of the heart which continues as the visceral pericardium c. Visceral pericardium d. Transverse Septum  Separates the pericardial cavity and the pleuroperitoneal cavity e. Pleuroperitoneal Cavity  contains the visceral organs (minus the heart)

  30. CHAMBERS OF THE HEART Sinus venosus  Dark colored triangular structure, connected to the ventral wall of the right atrium Left and Right atria  anterior, thin walled Ventricle  posterior, thick walled Conus arteriosus  bulb like, lies obliquely on the dorsal wall of the right atrium  base of all the arteries arises from the antero-ventral side of the ventricle * Contraction  Systole * Relaxation  Diastole

  31. Ventral Aspect • Ventricle • Right Atrium • Left Atrium • Conus Arteriosus • Truncus Arteriosus • Pulmocutaneous Artery • Systemic Artery • Common Carotid Artery

  32. Dorsal Aspect • Ventricle • Right Atrium • 3. Left Atrium • 4. Sinus Venosus • 5. Pulmonary Vein • 6. Pulmocutaneous Arches • 7. Systemic Arches • 8. Common Carotid Arches

  33. VENOUS SYSTEM Principal Divisions Systemic  carry unoxygenated blood from the different parts of the body directly to the right atrium Portal  carry unoxygenated blood through a system of blood capillaries in the liver or kidney from where the blood is recollected by systemic veins to be brought back to the right atrium of the heart Pulmonary  carry oxygenated blood from the lungs directly to the left atrium

  34. VEINS Left/Right Precaval veins  a.k.a. anterior vena cava  big blood vessels entering the Sinus venosus antero-lateral angles Postcaval vein  a.k.a. posterior vena cava Veins connected to the Anterior vena cava a. External jugular vein  anterior b. Innominate vein c. Subclavian vein  Brachial vein  Musculocutaneous vein

  35. PORTAL VEINS Hepatic Portal System Consist of the: • Hepatic portal vein  drains blood from the following tributaries gastric vein from the stomach splenic vein from the spleen pancreatic vein from the pancreas intestinal veins from the small intestines Ventral abdominal vein  brings the drained blood to the liver b. Hepatic vein

  36. PORTAL VEINS Renal Portal System Consist of the: a. Renal portal vein  lies on the lateral margin of the kidney alongside the mesonephric duct b. Veins that drain from the dorsal body wall c. Oviduct (for females) d. Femoral vein  anterior and dorsal sides of the thigh and the rest of the hindlimb e. Pelvic vein  medial branch of the femoral vein before joining the renal portal vein  course along the posterior abdominal wall, where they receive short veins from the urinary bladder, and then  unite ventrally to form the anterior abdominal vein f. Sciatic vein  posterior side of the thigh

  37. Pulmonary Veins  from the lungs they enter the left atrium

  38. ARTERIAL SYSTEM Arteries • thick-walled, light colored, generally deeply set in the body • blood flow is pulsating or in spurts • carry oxygenated blood (minus the pulmonary artery)

  39. ARTERIAL SYSTEM Ventral Side of the Heart Conus arteriosus  arises from the right antero ventral side of the ventricle  serves as the base of all arteries Truncus arteriosus  anterior of the conus arteriosus  immediately divides into the left and right trunks

  40. Arteries connected to the Truncus arteriosus Common carotid artery • anterior branch • divides into two branches: Internal carotid artery carotid gland round yellowish gland located near the base External carotid artery Systemic artery • middle branch • arches dorsally and posteriorly • gives small branches to the: Larynx, muscles of the jaw, dorsal side of the esophagus, orbit, nose, vertebral column Pulmocutaneous Artery

  41. Branches of Systemic Artery Subclavian artery  supplies the shoulder and neighboring parts  brachial artery: subclavian artery that continues to the forearm Pulmocutaneous artery  posterior Dorsal Aorta  posterior continuation of the unified left and right systemic arches Coeliaco-mesenteric artery  arising ventrally at the junction of the systemic arches and dorsal aorta  divides into the: coeliac artery anterior mesenteric artery

  42. Branches of Systemic Artery Posterior mesenteric artery  unpaired artery near the posterior end of the aorta, arising from its ventral side Left/Right common Iliac arteries  the split of the posterior end of the aorta Femoral artery  small dorsally directed artery posterior to the common iliac  supplies blood to the skin and muscles of the anterior part of the thigh Sciatic artery  common iliac artery that proceeds to the rest of the hindlimb

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