Post-Lab Discussion for Experiments 17-21 PDF

🐸 Post-Lab Discussion for Experiments 17-21 😋 E17: The Digestive System mechanically and chemically breaks down food into simpler molecules that can be absorbed and utilized by the cells in the body...

🐸 Post-Lab Discussion for Experiments 17-21 😋 E17: The Digestive System mechanically and chemically breaks down food into simpler molecules that can be absorbed and utilized by the cells in the body fecal waste → state of which food components cannot be broken down and excreted 2 Types: 1. Incomplete 2. Complete 😋 Incomplete Digestive System of the Fluke characterized by a digestive tract that ends blindly undigested waste material is egested through the mouth → “2-way street” (same exit and entry) 1. Round Oral Sucker → found at the tapered anterior end ; borders the mouth 2. Pharynx → a short, board tube found immediately after the mouth 3. Esophagus → follows the pharynx posteriorly ; very short 4. Intestines → where the esophagus eventually bifurcates a. Clonorchis sinensis → intestines consist of 2 linear branches ; do not open into any other orifice Post-Lab Discussion for Experiments 17-21 1  b. Fasciola gigantica → intestines consist of two main branches that send out several smaller branches laterally ; do not open into any other orifice 😋 Complete Digestive System of the Cockroach has an additional orifice for the exit of undigested waste material ; orifice can be in the form of an anus or a cloaca cockroaches → anus is the exit of feces and excretory waste 3 Divisions of the Digestive Tract 1. Foregut 2. Midgut 3. Hindgut Post-Lab Discussion for Experiments 17-21 2  😋 Foregut 1. Crop → most prominent feature of the foregut ; very wide 2. Esophagus → where the crop tapers anteriorly 3. Pharynx → where the esophagus tapers 4. Gizzard → a distinct chamber posterior to the crop 😋 Midgut Gastric Ceca - several tubular protrusions ; marks the posterior end of the midgut 😋 Hindgut 1. Malpighian Tubules → very fine threads seen at the junction between the midgut and hindgut Post-Lab Discussion for Experiments 17-21 3  2. Ileum → very thin anterior portion of the hindgut 3. Colon → main length of the hindgut 4. Rectum → follows the colon ; eventually terminates at the anus a. Anus 😋 Complete Digestive System of the Toad Toad → have a cloaca that serves an an exit for feces, urine, and gametes can be divided between the digestive tract and the digestive glands Digestive Tract - where food passes through Digestive Glands - are outgrowths which secretes enzymes toward the tract via ducts 😋 Buccal Cavity of Toad 1. Tongue → extensible ; connected to the floor of the mouth ; used to capture prey 2. Maxillary Teeth → line the maxillary arch ; not sharp ; just to keep mouth closed 3. Choanae or Internal Nares → paired openings found anteriorly ; help in grasping prey in the toad's mouth 4. Vomerine Teeth → ridges lined with serrations that are found posterior to the internal nares ; help in grasping prey in the toad's mouth 5. Esophagus → dorsal opening 6. Glottis → ventral slit-like opening surrounded by cartilage Post-Lab Discussion for Experiments 17-21 4  😋 Overview of the Toad Body Cavity 1. Coelom → space containing the visceral organs 2. Pleuro-peritoneal Cavity → part of the coelom located at the chest and the abdomen 3. Pericardial Cavity → contains the heart 4. Peritoneum → surface of the pleuro-peritoneal cavity ; composed of squamous epithelia and supporting connective tissue 5. Parietal Peritoneum → peritoneum that lines the inner body wall 6. Visceral Peritoneum → forms the surface of the organs 7. Mesenteries → continuations of the peritoneum that hold or suspend the organs in place ; are double membranes and can attach from the dorsal or ventral body wall organ to body wall ! 8. Omentum → double-membrane peritoneal derivative which serves to bridge or hold together certain visceral organs Post-Lab Discussion for Experiments 17-21 5  organ to organ ! 😋 Toad Digestive Tract rugae → folds of the stomach wall lumen → cavity of the stomach 1. Esophagus → a tubular organ that extends from the buccal cavity ; serves as a passageway of ingested food to the stomach 2. Stomach → a large, bean-shaped, muscular organ a. Cardiac End → anterior end of the stomach b. Pyloric End → posterior end of the stomach c. Lesser Curvature → medial surface of the stomach d. Greater Curvature → lateral surface of the stomach e. Pyloric Sphincter → a constriction that marks the boundary of the stomach and the small intestine f. Mesogaster → the dorsal mesentery that suspends the stomach at the cardiac end Post-Lab Discussion for Experiments 17-21 6  3. Small Intestine → coiled and tubular ; where most of the chemical digestion and absorption is completed a. Anterior Duodenum → runs parallel to the stomach b. Posterior Ileum → longer c. Mesentery Proper or Mesenterium → the dorsal and highly vascularized mesentery that suspends the small intestine d. Gastrohepato-duodenal Omentum or Lesser Omentum → translucent membrane stretching from the liver to the stomach (lesser curvature) and the duodenum 4. Large Intestine → large sac-like organ a. Mesorectum → dorsal mesentery that suspends the large intestine and spleen b. Spleen → small dark-colored ovoid organ suspended on a mesentery ; part of the lymphatic system 5. Cloacal Opening → leads to the large intestine via the cloaca 😋 Digestive Glands Post-Lab Discussion for Experiments 17-21 7  1. Liver → large dark colored organ composed of many lobes a. Right and Left Lobe → largest lobes of the liver i. Left Lobe → can be divided into anterior and posterior left lobe 2. Gall Bladder → round sac-like 1. Gallbladder organ suspended between the 2. Liver right and left lobes of the liver 3. Pancreas 3. Pancreas → an irregularly-shaped and elongated secretory organ embedded in the lesser omentum, near the duodenum and the stomach 😋 Microscopic Anatomy of the Small Intestine 1. Lumen → center of the section where food passes through 2. Valves of Kerckring → the permanent circular folds that line the small intestine Post-Lab Discussion for Experiments 17-21 8  3. Villi → fingerlike outgrowths that project into the lumen and line the valves of Kerckring 😋 Microscopic Anatomy of the Small Intestine — Layers from Out to In 1. Serosa → outermost later that is very thin ; also the visceral peritoneum ; where blood vessels, lymph spaces, and nerves can be found 2. Muscularis → outer to the submucosa ; composed of a thicker, inner stratum circulare and outer stratum longitudinale ; for contraction or peristaltic movement 3. Submucosa → outer to the mucosa ; composed of light-colored loose connective tissue ; follows the foldings of the villi ; where many lymph spaces and large blood vessels can be found 4. Mucosa → lined with columnar epithelial cells Interspersed among the columnar epithelia are the thicker and lighter- colored goblet cells which secrete mucus 😋 Microanatomy of the Frog Stomach — Layers Post-Lab Discussion for Experiments 17-21 9  Rugae → folds at the interior of the stomach's cross section ; functions to increase the surface area of the stomach 1. Mucosa → innermost layer ; has two layers a. Columnar Epithelial Layer → thinner and inner i. has many depressions called gastric pits which lead to the multicellular gastric glands ii. epithelial layer and the gastric pits are lined with columnar epithelial cells b. Lamina Propria → thicker, underlying ; where gastric glands and the connective tissue between them can be found i. different cells can be found in various areas of a gland 1. Neck → neck or Foveolar cells that secrete mucin 2. Base of Fundus → zymogenic or chief cells that secrete pepsinogen 3. Periphery of the Fundus or between the zymogenic cells → parietal cells that secrete gastric/hydrochloric acid 2. Muscularis Mucosa → thin ; immediately outer to the lamina propria, composed of inner stratum circulate and outer stratum longitudinale ; follows the folds of the rugae a. Stratum Circulare b. Stratum Longitudinale 3. Submucosa → outer to the muscularis mucosa, composed of light-colored loose connective tissue , follows the folds of the rugae, similar in composition and function to the small intestine's submucosa 4. Muscularis → very thick, composed of circular smooth muscle cells 5. Subserosa → much thinner, contains connective tissue, some blood vessels, and longitudinal smooth muscle strands 6. Serosa → very thin outermost layer Post-Lab Discussion for Experiments 17-21 10  1. Red Arrows → gastric pics 2. Yellow Arrows → gastric glands 😋 Microanatomy of the Frog Liver cross-section of the liver can be divided into polygonal liver lobules with a very large central vein at the middle of each lobule dark pigment granules → interspersed throughout the cross section ; the older you are, the more you have ; the waste product not filtered Individual Hepatocytes → can be identified by their nuclei and are arranged in irregular clusters Sinusoids → spaces between the cell clusters, where blood can be in contact with the cells Bile Ducts → come in various sizes ; walls are lined with cuboidal epithelial cells ; ducts may contain the greenish-gray tinted bile in their lumen Post-Lab Discussion for Experiments 17-21 11  Arterioles and Venules → have more layers in their walls ; many contain red blood cells Arterioles → have a thicker smooth muscle layer compared to venules Venules → larger 🌬️ E18: The Respiratory System Oxygen Influx and Carbon Dioxide Efflux → important for the continuation of aerobic cellular respiration in animals Respiration → process entailing the exchange of gases to and from the body ; done through various types of respiratory organs such as lungs, tracheary systems, gills, and even the integument 4 Conditions for Gas Exchange 1. High Surface Area 2. High Permeability 3. Contact with Oxygen-rich Medium 4. Exposure to Blood Circulation or Tissues Animals with thin, permeable, or highly vascularized integuments and high body volume- to-surface area ratio → simple gas diffusion through the integument Post-Lab Discussion for Experiments 17-21 12  🌬️ The Tracheal System of a Human Head Louse 1. Spiracles → openings to the respiratory system, seen at the sides of the animal at almost every segment 2. Trachea → tubes where the spiracles immediately open into 3. Tracheal Trunks → paired ; the largest tracheae ; run longitudinally near the slides of the animal a. Tracheoles → the tracheal trunks branch further into finer tubes , which terminate into the microscopic tracheoles , which are in direct contact with the tissues Air Sac → where oxygen can be stored 🌬️ Flow of Air in the Tracheal System of Insects 🌬️ Air from External Environment → Spiracles → Trachea → Tracheal Trunks → Tracheoles → Tissues Post-Lab Discussion for Experiments 17-21 13  🌬️ The Gill System of Fish 1. Operculum → a bony flap seen anterior to the pectoral fins ; protects the gills contained within the underlying space, the gill chamber 2. Gill Chamber → underlying space continuous with the buccal cavity 3. Gill Filaments → thin, elongated extensions that are attached to the bony gill arches ; house networks of capillaries a. Gill Arches → 4 pairs present 4. Gill Rakers → found on the inner surface of the gill arches ; are short and pointed ; protect gill filaments from debris 5. Pharyngeal Clefts → spaces between the arches 🌬️ Flow of Air In the Gill System of Fish Post-Lab Discussion for Experiments 17-21 14  🌬️ The Lung Systems of Toad — Positive Pressure Breathing 1. External Nares → at the dorsal aspect of the snout 2. Choanae or Internal Nares → paired anterior openings ; air coming through the external nares enter the buccal cavity via these openings 3. Openings of the Eustachian Tube → found at the angles of the jaw ; maintains pressure behind/front of tympanic membrane so ears don’t pop 4. Openings to Vocal Sacs (in Males) → In males, slit-like openings to the vocal sacs can be found ventral to each Eustachian tube opening 5. Glottis → a slit-like opening on the ventral midline at the buccal cavity ; closed when eating ; surrounded by two cartilages: the paired arytenoids immediately flanking it, and the cricoid that forms a ring around the arytenoid a. Arytenoids i. Pair of arytenoids - form a hemisphere ; lumen of this hemisphere which is continuous with the lumen of the cricoid ring ; together, these form the chamber of the larynx or voice box b. Cricoid 6. Larynx or Voice Box → houses paired thin flaps of connective tissue, the vocal cords 7. Vocal Cords → produce the croaking sound of the animal through vibrations caused by the passage of air through the larynx Post-Lab Discussion for Experiments 17-21 15  8. Bronchial Tubes → Air comes from the lungs which are connected to the larynx by a pair of bronchial tubes 9. Lungs → paired and sac-like ; seen at the antero-lateral end of the pleuro- peritoneal cavity, dorsal to the liver 🌬️ Flow of Air in the Lung System of Toad — Positive Pressure Breathing 🌬️ Air from External Environment → External Nares → Internal Nares → Buccal Cavity Floor → Glottis → Larynx → Trachea → Bronchial Tubes → Lungs 🌬️ Lung System of Humans — Negative Pressure Breathing Post-Lab Discussion for Experiments 17-21 16  Inspiration → Thoracic Cavity expands, External Intercostal Muscles contract → Diaphragm contracts Expiration → Thoracic Cavity reduces, External Intercostal Muscles relax → Diaphragm relaxes mylohyoid in toad is homologous to diaphragm in mammals 🫀 E19: The Circulatory System the transport of gases , nutrients , and other substances to and from different parts of the body 2 Types: 1. Closed Circulatory System → blood is transported via vessels ; exhibited by vertebrates, annelids, and cephalopods 2. Open Circulatory System → blood or hemolymph freely moves within the body cavity ; exhibited by arthropods and most mollusks body (movement) is the main driver of circulation Flatworms and Sponges → do not have a circulatory system ; blood is transported between cells and tissues by body movements instead 🫀 Open Circulatory System of the Cockroach 1. Dorsal Aorta → medially-located membranous tube ; runs along the thorax and continues into the abdomen as the heart Post-Lab Discussion for Experiments 17-21 17  2. Heart → divided into diamond-shaped chambers which are guarded by valves known as ostia 3. Ostia → allow the inflow of hemolymph which its valves prevent backflow 4. Pericardial Sinus → cavity where the heart is located 5. Dorsal Diaphragm → a membranous sheet that separates the pericardial sinus from the rest of the body 1. Heart Chambers 2. Dorsal Aorta 3. Ostia (Valved Openings) → open to allow inflow of hemolymph from the body cavity to the hemocoel ; valves that also prevent the backflow of hemolymph from the hemocoel back to the body cavity 4. Dorsal Diaphragm → separates the pericardial sinus from the rest of the body Anterior to the heart, the aorta lacks valves or musculature ; it is a simple tube which continues forward to the head and empties near the brain Hemolymph bathes the organs and muscles of the head as it emerges Post-Lab Discussion for Experiments 17-21 18  from the aorta, and then haphazardly percolates through the body until it reaches the abdomen and re-enters the heart Thus, blood flow to organs is facilitated by animal movement It delivers nutrients and hormones to cells and removes waste During each diastolic phase (relaxation), the ostia (valved openings) open to allow inflow of hemolymph from the body cavity 🫀 Circulatory Systems of Vertebrates 1. Blood 2. Heart → serves as the pump, sending blood to the different parts of the body via the arteries 3. Arteries → bring blood away from the heart 4. Arterioles 5. Veins → return blood to the heart 6. Venules 7. Capillaries → where gas and nutrient exchange occur ; found in between smaller arteries, the arterioles , and venules (smaller veins) Arteries and Veins → distinguished from each other in histology by their walls - the artery having thicker , muscular walls 🫀 Closed Circulatory System of the Toad Post-Lab Discussion for Experiments 17-21 19  Toad Heart → a bulbous structure found within the pericardial cavity, a cavity Visceral Pericardium → a membranous layer that covers the surface of the heart and is continuous with the lining of the whole cavity Parietal Pericardium or the Parietal Sac → the lining of the whole cavity Toad Heart → composed of the sinus venosus , conus arteriosus , and three chambers: 2 atria and a large ventricle Ventricle → most prominent part of the heart ; a large , highly muscular , triangular structure 2 Atria → thin-walled ; anterior and lateral to the ventricle Conus Arteriosus → a bulb-like structure that lies in between the atria and slightly obstructs the right atrium from view Sinus Venosus → dark-colored pulsating structure ; receives all deoxygenated blood from the body and deposits it into the right atrium Interatrial Septum → separates the 2 atria Sinoatrial Aperture → an opening found in the dorsal wall of the right atrium which serves as the entrance of blood from the sinus venosus On the wall of the left atrium , an opening which connects to the pulmonary vein can be found Blood passes through the right and left atrium towards the ventricle via the right and left atrioventricular apertures respectively ; Valves guard these openings to prevent the backflow of blood 2 Valves guard the opening to the conus arteriosus 1. Spiral Valve → direct blood flow in conus arteriosus 2. Semilunar Valve → prevent backflow of blood into ventricle ; guard opening of ventricle in truncus arteriosus Post-Lab Discussion for Experiments 17-21 20  Trabeculae Carnae → strengthens the walls ; prevents suction when heart chambers contract 🫀 Toad Venous System veins → dark, thin-walled structures consists of 3 Types of Veins: 1. Systemic Veins → carry deoxygenated blood into the sinus venosus 2. Portal Veins → carry deoxygenated blood into a filtering organ 3. Pulmonary Veins → carry oxygenated blood from the lungs directly into the left atrium ; seen exiting the lungs and entering the left atrium Tributaries → branches of the veins Left and Right Precaval Veins or Anterior Vena Cavae → blood vessels entering antero- laterally 3 Main Tributaries of the Precava 1. Anterior External Jugular → runs anteriorly, divides into the lingual and maxillary veins a. Lingual Vein → drains the tongue Post-Lab Discussion for Experiments 17-21 21  b. Maxillary Vein → drains the lower jaw 2. Middle Innominate → usually short, divides into the internal jugular and subscapular veins a. Internal Jugular Vein → drains the brain b. Subscapular Vein → drains the shoulder 3. Posterior Subclavian Veins → divides into the brachial and musculotaneous veins before entering the arm a. Brachial Vein → continues onward and drains the arm b. Musculotaneous Vein → exits the pleuro-peritoneal cavity ; drains the skin and chest muscles Post Caval Vein or Posterior Vena Cava → enters the sinus venosus on its posterior end Hepatic Veins → the pair of branches that drain the liver which is sent by the post cava Renal Veins → the post cava terminates at the level of the kidney after sending several pairs of branches to drain the organ 2 Portal Systems in the Toad 1. Hepatic Portal System Hepatic Portal Vein → seen coming from the lobes of the liver embedded on the mesentery of the intestine ; has tributaries to the different organs of the digestive system 1. Gastric Vein → drains the stomach 2. Pancreatic Vein → drains the pancreas 3. Splenic Vein → drains the spleen 4. Intestinal Vein → drains the small intestine Ventral Abdominal Vein → joins the hepatic portal vein before entering the liver ; drains the muscles of the abdomen ; seen to be formed by the union of the 2 pelvic veins Post-Lab Discussion for Experiments 17-21 22  2 Pelvic Veins → usually attached to the ventral body wall 2. Renal Portal System Renal Portal Vein → drains the femoral vein and the sciatic vein 1. Femoral Vein → drains the thighs 2. Sciatic Vein → drains the shank and pes Pelvic Vein → will be seen to join the femoral vein before the latter enters the renal portal vein 20 → Precaval Vein, 10 → External Jugular: 13 → Pulmonary Veins lingual and the maxillary veins which drain the tongue and lower jaw, 11 → Innominate Vein: Internal Jugular and Subscapular Veins which drain the brain and shoulders, 12 → Subclavian Vein, 21 → Brachial Vein, 22 → Musculocutaneos Vein which drains the skin and chest muscles Post-Lab Discussion for Experiments 17-21 23  24 → Gastric Vein 20 → Pre-caval Veins, 15 → Post-cava, 14 → Hepatic Veins, 23 → Hepatic Portal Vein, 18 → Ventral Abdominal Vein (the blood vessel under linea alba) 25 → Pancreatic Vein, 26 → Splenic Vein, 28 15 → PCV, 17 → Renal Veins, 18 → Ventral → Spleen Abdominal Vein Post-Lab Discussion for Experiments 17-21 24  16 → Renal Portal Vein 🫀 Toad Arterial System Arteries → can be distinguished by their light color ; usually found dorsal to the venous system ; carry oxygenated blood except for the pulmocutaneous artery 3 Branches of the Paired Truncus Arteriosus 1. Common Carotid Artery → the most anterior branch of the truncus arteriosus ; divides into the external carotid artery and the internal carotid artery Internal Carotid Artery → easily identifiable by the presence of a dark bulb, the carotid body 2. Systemic Arch → formed by the second branch of the truncus arteriosus ; passes dorsally and laterally while sending smaller arteries to the larynx, the dorsal side of the esophagus, orbit, nose, and the vertebral column ; also supplies blood to the muscles of the jaw ; merge to form dorsal aorta Subclavian Artery → will branch off laterally from the systemic arch and will continue as the brachial artery in the forelimb Post-Lab Discussion for Experiments 17-21 25  3. Pulmocutaneous Artery → most posterior branch ; has 2 branches a. Pulmonary Artery → continuous posteriorly and will enter the lungs b. Cutaneous Artery → branches laterally off the main trunk towards the skin of the back Dorsal Aorta → formed through the medial union of the systemic arteries from both sides 1. Coeliacomesenteric Artery → first branch out of the aorta ; has 2 branches a. Coeliac Artery - branches off into the gastric , hepatic , and pancreatic arteries b. Anterior Mesenteric Artery - branches off into the intestinal and splenic arteries 2. Renal Arteries → branch off from the dorsal aorta and enter the kidney dorsally 3. Posterior Mesenteric Artery → supplies the large intestine Dorsal Aorta ends by splitting into the left and right common iliac arteries, which gives off 2 branches 1. Lateral Femoral Artery → supplies the skin and muscles of the anterior thigh 2. Median Sciatic Artery → supplies the rest of the hind limb Post-Lab Discussion for Experiments 17-21 26  42 → Truncus Arteriosus ; Arteries bring Orange → Common Carotid Artery, 31 → blood away from the heart External Carotid Artery - Tongue, 32 → Internal Carotid Artery - mouth, brain, eye , 43 → Carotid Body, 34 → Systemic Arch, 33 → Pulmocutaneous Artery, 35 → Pulmonary Artery, 46 → Cutaneous Artery (continuous into the inner surface of the skin of the back) 34 → Systemic Arch, 44 → Subclavian Artery 34 → Systemic Arch, 44 → Subclavian Artery, (right beside brachial nerve) 37 → Dorsal Aorta, 36 → Coeliacomesentric Artery, 47 → Coeliac Artery (branches off into the gastric, hepatic, and pancreatic arteries), 38 → Anterior Mesentertic Artery (branches off into the intestinal and splenic arteries Post-Lab Discussion for Experiments 17-21 27  37 → Dorsal Aorta, 39 → Renal Artery, 40 → 37 → Dorsal Aorta, 39 → Renal Artery, 40 → Posterior Mesenteric Artery, 53 → Common Posterior Mesenteric Artery, 53 → Common Iliac Arteries Iliac Arteries, 54 → Femoral Artery, 41 → Sciatic Artery 🫀 Blood Tracing from Tongue to Lungs (PPT Notes) 🫀 Lingual → External Jugular → Precaval → Sinus Venosus → Right Atrium → Ventricle → Conus Arteriosus →Truncus Arteriosus → Pulmocutaneous Artery → Pulmonary Artery → Lungs 🫀 Blood Tracing from Lungs to Stomach (PPT Notes) 🫀 Lungs → Pulmonary Vein → Left Atrium → Ventricle → Conus Arteriosus → Truncus Arteriosus → Systemic Artery → Coeliacomesenteric Artery → Coeliac Artery → Gastric Artery 🫀 Blood Tracing (PPT Slide) Post-Lab Discussion for Experiments 17-21 28  Black Font → mixed oxygenated/deoxygenated blood Red → deoxygenated Blue → oxygenated 🫀 Closed Circulatory System of Mammals Base → larger, anterior end Apex → narrower, posterior end Coronary Veins and Arteries → small blood vessels that cover the heart ; serve to drain and supply the cardiac muscles respectively Mammalian Heart → composed of 4 chambers: 2 anterior atria and 2 posterior ventricles Ventricles → have thick, muscular walls with the left chamber being more muscular than the right Trabeculae Carnae → ridges found on the walls of the two ventricles Interventricular Septum → separates the two ventricles into left and right chambers Interatrial Septum → divides the two atria Atrioventricular Aperture → an opening found between the atrium and the ventricle Post-Lab Discussion for Experiments 17-21 29  Mitral or Bicuspid Valve → two membranous flaps that border the atrioventricular aperture on the left side Tricuspid Valve → three flaps that border the atrioventricular aperture on the right side The ventricles are connected to projections from the wall of the ventricles, the papillary muscles, via tough thread-like structures, the chordae tendinae Papillary Muscles & Chordae Tendinae → aid in the opening and closing of the valves The opening leading out of the right atrium leads to the pre-caval and post- caval veins Opening of the Pulmonary Artery → can be found from the right ventricle Semilunar Valve → found along the opening to the pulmonary artery as half- moon flaps slightly covering the opening of the artery Pulmonary Vein → how blood from the lungs enters the left atrium Aorta → how the left ventricle sends blood to the body Sinus Venosus in Mammals → has been reduced to the sino-atrial node, found at the area where the pre-and postcaval veins exit the left atrium 🫀 Blood Tracing in Mammalian Heart Post-Lab Discussion for Experiments 17-21 30  🫀 Precava/postcava → right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta 1 → Right Atrium, 2 → Right Ventricle, 3 → Left Atrium, 4 → Left Ventricle, 5 → Pulmonary Artery, 6 → Coronary Veins 💩 E20: The Excretory System Excretion → process of removal of nitrogenous metabolic wastes via organs of filtration ; organs also serve as osmoregulators, removing excess fluids and salts solid waste → not absorbed liquid waste (discussed in E20) → absorbed but no longer needed, so it is excreted Forms of Excretory Organs 1. Protonephridia → present in lower metazoans such as flatworms 2. Metanephridia → present in mollusks and annelids 3. Antennal Gland → present in crustaceans Post-Lab Discussion for Experiments 17-21 31  4. Malpighian Tubules → present in terrestrial arthropods 5. Kidneys → present in vertebrates In unicellular animals and some invertebrates, there are no specialized organs for excretion ; wastes are simply removed through diffusion at the cell membrane or epithelium Nitrogenous Wastes → excreted either as ammonia, urea, or uric acid Metanephridia of Annelids and Mollusks → Protonephridia of Flatworms → excretes excreted Ammonia Ammonia Antennal Gland of Crustaceans → excretes Coxal Gland of Arachnids → excretes Uric Ammonia Acid ; the gland accumulates excess ions (may be venom) for paralyzing prey ; arachnids also have malpighian tubules 🗒️ Excretory Organs and Nitrogenous Wastes per Animal Group Post-Lab Discussion for Experiments 17-21 32  Animal Group Excretory Organ Main Nitrogenous Waste Flatworms Protonephridia Ammonia Mollusks Metanephridia Ammonia Crustaceans Antennal Gland Ammonia Terrestrial Arthropods Malpighian Tubules Uric Acid Fishes Mesonephric Kidney Ammonia Amphibians Mesonephric Kidney Urea Reptiles Metanephric Kidney Uric Acid Birds Metanephric Kidney Uric Acid Mammals Metanephric Kidney Urea Arachnids Coxal Gland Uric Acid 💩 Malpighian Tubules of the Cockroach very small and fine thread-like diverticula at the border of the midgut and the hindgut tubules produce waste as crystalline uric acid which is excreted together with the feces via the anus Post-Lab Discussion for Experiments 17-21 33  💩 Mesonephric Kidneys of Toad two dark-colored, ovoid organs Cisterna Magna → space occupied by the toad kidneys ; also called the retroperitoneal space Kidneys of the Toad → referred to as retroperitoneal because of their location relative to the peritoneum Wolffian or Mesonephric Duct → lies on the lateral surface of the kidney, descends posteriorly to the urinary bladder Urinary Bladder → large, delicate, sac-like organ at the ventral side of the pelvis ; its contents exit to the cloaca Adrenal Glands → yellow streak seen on the ventral surface of each kidney In male toads, the kidneys are dorsal to the ovoid and light-colored testes , which are located dorsal to the large intestine Kidney section of the frog is ovoid , its dorsal side is convex , and its ventral side is concave in some slides, the ventral gonads and scattered fat globules can be seen Malpighian bodies or renal corpuscles → primary filtration sites of blood in the kidney ; dark spots arranged in a curve along the ventral length of the kidney section Glomerulus → dark, round mass of capillaries in the malpighian bodies Post-Lab Discussion for Experiments 17-21 34  Bowman's Capsule → immediate, very thin crest of squamous epithelia in malpighian bodies 2 Types of Tubules Present in the Toad Kidney 1. Coiled Uriniferous Tubules → sites of reabsorption of water and other substances ; located next to the renal corpuscles and can have elongated lumen ; the start of active absorption 2. Round Collecting Tubules → located at the convex margin of the section, have wider and circular lumen, and are lined with prominent cuboidal epithelia ; tubules all converge at the mesonephric duct ; the urine is already mostly concentrated, so their main purpose is to collect Base of the mesonephric duct appears triangular ; A section of the renal portal vein might be seen along with part of the mesonephric duct Renal Artery → section may be seen at the dorsal surface of the kidney Renal Vein → a section can be seen at the ventral surface Adrenal Gland → small mass of cells that can be seen at the ventral surface ; cells are notably different from the bulk of the kidney Post-Lab Discussion for Experiments 17-21 35  1 → Adrenal Gland (produces coerticosteroids 1 → Mesonephric Duct, 2 → Renal Portal Vein, including adrenaline), 2 → Mesonephric 3 → Collecting Tubules, 4 → Uriniferous Kidney, 3 → Urinary Bladder, 4 → Tubule, 5 → Renal Corpuscle/Malpighian Mesonephric Duct (in mammals, this Tubule (where filtration of blood happens), 5a becomes the vas deferens in males, 5 → → Glomerulus, 5b → Bowman’s Capsule, 6 → cloaca Renal Vein, 7 → Adrenal Gland, 8 → Renal Artery Fat bodies and testis as landmarks ; Kidney is located right behind the dorsal parietal peritoneum, within the cisterna magna/retroperitoneal space 3 → Collecting Tubules, 4 → Uriniferous 6 → Renal Vein, 7 → Adrenal Gland Tubule, 5 → Renal Corpuscle/Malpighian Tubule (where filtration of blood happens), 8 → Renal Artery Post-Lab Discussion for Experiments 17-21 36  💩 Formation and Excretion of Urine in Toad Kidney 💩 Renal Artery & Renal Portal Vein → Glomerulus → Uriniferous Tubule → Collecting Tubule → Mesonephric Duct → Urinary Bladder → Cloaca → Cloacal Opening → External Environment 💩 Metanephric Kidney of Mammals can be divided into 2 regions 1. Outer Cortex → contains the renal corpuscles and the distal and proximal tubules 2. Inner Medulla → contains the loop of Henle and the collecting tubules Microscopic collecting tubules - terminate at the renal papilla number of papillae varies with the species pig → individual papillae converge to form the triangular renal pelvis cat → only one papilla Renal pelvis tapers to form the metanephric duct or ureter , which emerges from the medial surface of the kidney and continues towards the urinary bladder Hilus → concavity of the kidney where the renal pelvis is located and where the ureter emerges ; also where the renal artery and vein enters the kidney Post-Lab Discussion for Experiments 17-21 37  1 → Cortex, 2 → Medulla, 3 → Renal Papillae, 4 → Renal Pelvis, 5 → Ureter/Metanephric Toxicity corresponds to water requirement for Duct, 6 → Hilus dilution 💩 Formation and Excretion of Urine in Mammalian Kidney 💩 Glomerulus (Cortex) → Proximal Tubule (Cortex) → Descending Limb of Loop of Henle ( Medulla) → Ascending Limb of Loop of Henle (Medulla) → Distal Tubule (Cortex) → Collecting Tubules (Cortex to Medulla)→ Renal Papilla → Pelvis → Ureter → Bladder → Urethra → External Environment 😰 Nervous System Post-Lab Discussion for Experiments 17-21 38  responsible for perception of stimuli, transmission of sensory signals or impulses to the central nervous system and the induction by the CNS for the action of muscles and glands coordinates and integrates various bodily functions ; role provides a way for complex, multicellular animals to function as a single unit in smaller organisms and less complex animals (ex. sponges), coordination of various functions is done in the cellular or organelle level 4 Types of Nervous 1. Diffuse Type or Nerve Net → found in radially symmetrical animals, except echinoderms ; consists of a network of nerve cells almost evenly spread across the body of the animal Example: Hydra 2. Ladder Type → found in animals like flatworms ; nerve cords are organized in a ladderlike manner which runs along the antero-posterior axis pair of ganglia → located in the head region ; are functional clusters of neurons example: Planaria sp 3. Ganglionic Type → found in annelids (earthworms) and arthropods ; has a dorsal and anterior cerebral ganglion or brain Ventral Nerve Cords → extend posteriorly from the cerebral ganglion Ganglia → form a chain along the nerve cord each pair of ganglia in each segment is connected by nerve strands 4. Tubular Type → found in vertebrates ; referred to as tubular because of the presence of internal spaces in the brain and spinal cord brain → spaces are called ventricles, which continue as the central canal in the spinal cord spinal cord → located dorsally unlike the nerve cords of the ganglionic nervous system Post-Lab Discussion for Experiments 17-21 39  Diffuse/Nerve Net → cnidarians ; Ladder → Platyhelminthes ; Ganglionic → Rotifers, mollusks, annelids, nematodes, arthropods ; Nerve Ring → Echinoderms 😰 Ganglionic Nervous System of the Cockroach Nerve Cords → extends posteriorly from the cerebral ganglion ganglia and the nerve strands → interconnect the cerebral ganglion have prominent paired sense organs 1. Compound Eyes 1 → Antenna, 2 → Compound Eye, 3 → Nerve 2. Antennae Cords, 4 → Ganglion (There is a ganglion per segment) 😰 Tubular Nervous System of the Toad Post-Lab Discussion for Experiments 17-21 40  can be divided into: 1. Central Nervous System (CNS) → includes the brain and the spinal cord 2. Peripheral Nervous System (PNS) → includes the somatic nervous system and the autonomic or visceral nervous Tubular Nervous System of Vertebrates system includes the motor and sensory nerves that emerge from the brain (cranial nerves) and spinal cord (spinal nerves) allows for the relay of sensory information and also of the signals for voluntary and involuntary movements 😰 Peripheral Nervous System (PNS) Nerves → light-colored and shiny in appearance 1. 1st, 2nd, and 3rd Spinal Nerves → found very close to each other, at the level of the forelimb ; near the level of the shoulder , the 3 spinal nerves will fuse to form the brachial plexus and then separate further on a. 1st Spinal Nerve → innervates the tongue , jaw , and hyoid b. 2nd Spinal Nerve → largest of the three ; will continue into the forelimb as the brachial nerve c. 3rd Spinal Nerve → innervates the shoulder Post-Lab Discussion for Experiments 17-21 41  2. 4th, 5th, and 6th Spinal Nerves → found posteriorly between the pectoral and pelvic girdles ; innervates the muscles and skin of the body wall 3. 7th, 8th, and 9th Spinal Nerves → large nerves emerging at the level of the pelvis ; proceed posteriorly then fuse to form the sciatic plexus a. 7th Spinal Nerve → innervates the large intestine, the bladder, and the oviducts (in females) b. 8th and 9th Spinal Nerve → continue into the hindlimb as the sciatic nerve 4. 10th Spinal nerve → small and lies close to the side of the urostyle ; innervates the cloaca, the bladder, and the oviducts (in females) 1 → 1st Spinal Verve/Hypoglossal (tongue, jaws, hyoid), 2 → 2nd Spinal Nerve/Brachial Nerve (Forelimb), 3 → 3d Spinal Nerve (Shoulder), 4 → Brachial Plexus, 5 → 7th Spinal Nerve (Large Intestine, Bladder, Oviducts), 6 → 8th Spinal Nerve, 7 → 9th Spinal Nerve, 8 → Sciatic Nerve (Hindlimb), 9 → Brachial Enlargement, 10 → 4th Spinal Nerve (Muscles and Skin of Body Wall), 11 → 5th Spinal Nerve (Muscles and Skin of Body Wall), 12 → Lumbar Enlargement, 13 → 6th Spinal Nerve ( (Muscles and Skin of Body Wall), 14 → 10th Spinal Nerve (Bladder, Cloaca, Oviducts), 15 → Sciatic Plexus, 16 → Filum Terminale Post-Lab Discussion for Experiments 17-21 42  1 → Brachial Plexus, 2 → 4th Spinal Nerve (Muscles and Skin of Body Wall), 3 → 5th Spinal Nerve (Muscles and Skin of Body Wall), 4 → Lumbar Enlargement, 5 → Sciatic Plexus, 6 → 10th Spinal Nerve (Bladder, Cloaca, Oviducts) 😰 Central Nervous System (CNS) 😰 Brain closely covered by the meninges : the inner pia mater and the outer dura mater Ventricles → inner cavities of the brain continuous with the central canal of the spinal cord both pia mater and dura mater contain cerebrospinal fluid Olfactory Bulb → anterior-most part of the brain Remnants of the olfactory nerves → observed emerging from the olfactory bulb anteriorly Rhinocoele → ventricle within the olfactory bulb Telencephalon or Ceberal Hemispheres → are paired, elongated, and oval ; posterior to the bulbs ; separated by a medial groove Post-Lab Discussion for Experiments 17-21 43  Lateral Ventricles → contained within the cerebral hemispheres ; converge posteriorly into the foramen of Monro Diencephalon → a small and unpaired lobe found posterior to the telencephalon 3rd Ventricle → cavity within the diencephalon Pineal Gland or Epiphysis → an endocrine gland found on the dorsal side of the diencephalon ; secretes melatonin (humans) ; supposed to be for visual function (toad) Anterior Choroid Plexus → a heavily-vascularized structure that covers the diencephalon that consists of cerebrospinal fluid-producing ependymal cells Mesencephalon → posterior to the diencephalon that is marked by optic lobes, paired ovoid structures protruding dorsally Optic Ventricles or Opticoeles → contained within the mesencephalon Remnants of the Optic Nerves → seen at the ventral side of the mesencephalon Optic Chiasma → where a fairly wide point of convergence of these optic nerves are founded at the mid-ventral side Bi-lobed infundibulum → an extension of the diencephalon found immediately posterior to the diencephalon Small Pituitary Body or hypophysis → posterior to the infundibulum ; regulate estrogen, progesterone, and testosterone Metencephalon or Cerebellum → thin fold ; houses the aqueduct of Sylvius which connects the optic ventricles with the fourth ventricle Triangular Myelecephalon or Medulla Oblongata → has a dorsal triangular opening, leading to the fourth ventricle ; opening is covered by the posterior choroid plexus Filum terminale → the tapered posterior end where the spinal cord extends after the myelencephalon Dorsal Median Sulcus → the mid-dorsal groove along the spinal cord Post-Lab Discussion for Experiments 17-21 44  Ventral Median Fissure → ventral counterpart of the dorsal median sulcus Ventricles of the brain → continuous with the central canal of the spinal cord 2 Enlargements Present along the Cord 1. Anterior Brachial Enlargement → correspond to the points of emergence of spinal nerves for the forelimbs 2. Posterior Lumbar Enlargement → correspond to the points of emergence of spinal nerves for the hindlimb The filum terminale and the elongated roots of the posterior spinal nerves form the feather-like cauda equina Post-Lab Discussion for Experiments 17-21 45  1 → Olfactory Nerve, 2 → Olfactory Bulb, 3 → Telencephalon or Cerebrum, 4 → Diencephalon, 5 → Pineal Gland (secrete melatonin in humans, seems vestigial in toads but can develop into a third eye ; pineal organ had a visual role which got lost during evolution), 6 → Mesencephalon or Optic Lobes At the Ventral Side of the Mesencephalon: 7 → Infundibulum (extension of diencephalon; connects pituitary gland to hypothalamus ; gives rise to the posterior part of the pituitary gland), 8 → Optic Chiasma, 9 → Optic Nerve, 10 → Pituitary Body (secrete hormones that regulate estrogen, progesterone, testosterone levels for 1. Growth and 2. Neural Function) Cavities inside the Brain: 30 → Rhinocoele, 31 → Lateral Ventricles, 32 → Foramen of Monro, 33 → 3rd Ventricle, 34 → Optic Ventricles, 35 → Aqueduct of Sylvius, 36 → 4th Ventricle Post-Lab Discussion for Experiments 17-21 46  Showing the choroid plexus Telencephalon → controls voluntary actions, senses and memory formation ; Diencephalon → regulation of visceral activities and metabolic homeostasis ; Mesencephalon → Visual and Auditory Reflex Center ; Metencephalon → muscle coordination ; Myelenchephalon → reflex center, controls autonomic functions: respiration, heart rate, blood vessel dilation, and constriction 🗒️ Summary: Brain Regions Brain Region Cavities Within Function Olfactory Bulb Rhinocoele smell Telencephalon (Cerebral Lateral Ventricles ; voluntary actions, senses and Hemispheres) Foramen of Monro memory formation 3rd Ventricle ; Optic visceral activities and metabolic Diencephalon Nerves ; Optic Chiasma homeostasis Mesencephalon (Optic Opticoeles ; Infundibulum visual and auditory reflex Lobes) ; Pituitary Body Metencephalon Aqueduct of Sylvius muscle coordination (Cerebellum) autonomic functions: respiration, Myelencephalon 4th Ventricle heart rate, blood vessel dilation and constriction Post-Lab Discussion for Experiments 17-21 47  😰 Spinal Cord housed within the neural canals of the vertebral column 2 General Areas in the Spinal Cord Section 1. Outer White Matter → consists of myelinated nerve fibers and supporting cells, the neuroglia or glial cells 2. Inner Grey Matter → consists of some neuroglia and neurons Central Canal → small cavity at the middle of the spinal cord section ; line with cerebrospinal fluid-producing ependymal cells Fissures → can be found at the ventral and dorsal side of the spinal cord Ventral Fissure (Ventral Median Fissure) → found adjacent to the ventral spinal artery ; wider Dorsal Fissure (Dorsal Median Sulcus) → found on the other side ; narrower Dorsal Cornua → the narrower pair at the dorsal side of the grey matter ; seen projecting into the white matte Ventral Cornua → other, wider pair at the ventral side of the grey matter These cornua contain axons which are continuous to the outside as the spinal nerves Dorsal Cornua→ for afferent nerves Ventral Cornua → for efferent nerves 2 Connective Tissue Layers Covering the Spinal Cord 1. Dura Mater → outer and loose 2. Pia Mater → inner and thinner ; has some veins and adipose tissue Subdural Space → the space between the connective tissue layers Post-Lab Discussion for Experiments 17-21 48  1 → Dorsal Fissure, 2 → Dorsal Cornua, 3 → Pia Mater, 4 → Subdural Space, 5 → Dura Mater, 6 → Ventral Cornua, 7 → White Matter, 8 → Grey Matter, 9 → Ventral Spinal Artery, 10 → Ventral Fissure, 11 → Ependymal Cells (produce cerebrospinal fluids), 12 → central canal 😰 Sense Organs 😰 Eyes pair of sensory organs responsible for visual perception Cornea → transparent portion at the front of the eye just exterior to the pupil or the eye's opening Conjunctiva → a very thin and translucent membrane that surrounds the cornea ; is continuous with the inner surface of the eyelids Sclerotic Coat or Sclera → tough whitish membrane found underneath the conjunctiva and wrapped around the eyeball ; maintains the shape of the eye Optic Nerve → thread-like ; found at the posterior end Retractor Bulbi → muscles around the optic nerve that is attached to the sclera ; pull the eye in place within the orbit Post-Lab Discussion for Experiments 17-21 49  Lens → opaque, spherical I → Iris, L → Lens, P → Pupil, C → Cornea, S → Sclera, O → Optic Nerve | 1 → Eyelids, 2 → Conjunctiva, 3 → Cornea, 4 → Sclera, 5 → Lens, 6 → Optic Nerve, 7 → Retractor Bulbi 😰 Ears paired organs responsible for auditory perception Parts of the Inner Ear 1. Tympanic Membranes or Tympana 2. Columella → very thin, elongated bone that extends to the interior of the ear 3. Eustachian Tube Post-Lab Discussion for Experiments 17-21 50  The space interior to the tympanic membrane is continuous with the buccal cavity via the Eustachian Tube Post-Lab Discussion for Experiments 17-21 51