fetal pig dissection questions.txt

  1. Terms
    • Anterior �C near head
    • Posterior �C near rear
    • Dorsal �C near front
    • Ventral �C near back
  2. Vestibule?
    the area between the lips and the teeth.
  3. Tongue?
    • This elongated muscular structure is readily visible upon the floor of the mouth. It is attached vertically along much of its length by a membrane, the?lingual frenulum,?and posteriorly to the?hyoid?bone.
    • The surface of the tongue is covered by variously shaped projections known as sensory?papillae.
    • Rolls food into balls/boli and pushes them to the back of the mouth cavity for swallowing.
  4. Palate:?
    This structure forms the roof of the mouth. It is a partition which separates the oral from the nasal cavity. Can produce certain sounds when functioning in conjunction with other organs
  5. Hard Palate:
    This is the bony anterior portion of the palate. A series of transverse ridges, the palatine rugae, cross the roof of the mouth.
  6. Soft Palate
    This is the posterior continuation of the palate. It is a muscular structure with bony support. It divides the oropharynx ventrally from the nasopharynx dorsally. In man there is a finger-like process, the uvula, which hangs down from its center posteriorly. It is absent in the pig.
  7. Epiglottis?
    • This cone-shaped flap of cartilage is located at the top of the larynx (voice box) near the base of the tongue. It protects the glottis, the slit-like opening to the trachea. During swallowing and eating the epiglottis prevents food from entering the trachea.
    • Thin elastic cartilaginous structure located at the root of the tongue that folds over the glottis to prevent food and liquid from entering the trachea during act of swallowing.
  8. Trachea?
    • This tube is commonly called the windpipe. It is topped by the epiglottis and larynx. It is kept open by rings of cartilage which extend around the trachea at intervals. They are incomplete dorsally. The trachea branches to form two bronchi which enter the lungs.
    • A thin-walled tube of cartilaginous and membrane tissue descending from the larynx to the bronchi and carrying air to the lungs.
    • The overall external texture of the trachea is rough and bumpy due to the tracheal cartilaginous rings. Slightly raised cartilaginous rings in a tube.
    • Cartilaginous rings: Prevent the trachea from collapsing when you breath out; no air in trachea.
  9. Esophagus?
    • This muscular tube, located dorsal to the trachea is also known as the gullet. Unlike the trachea, however, it is collapsed. Food is pushed forward in the esophagus by the rhythmic contractions of its walls, a process knows as peristalsis.
    • The esophagus extends posteriorly and dorsally within the thorax, then passes through the diaphragm into the abdominal cavity where it ends at the stomach
    • In order to find the trachea and esophagus use two wooden probes. With one, penetrate the glottis and pass into the trachea. Move the probe up and down and observe the movement of the trachea. With the second probe enter the esophagus dorsal to the glottis. Move it up and down and observe the corresponding movement of the esophagus.
    • The muscular, membrane tube for passage of food from pharynx to stomach.
    • Esophagus is attached to the stomach.
  10. Cardiac Sphincter Muscle
    • Controls the passage from the esophagus into the stomach; sphincter muscles normally limit passage to one direction.
    • Stops food from going back up the esophagus
  11. Pyloric Sphincter Muscle
    • Controls the passage from the stomach to the duodenum.
    • Stops bile and digested food from entering the stomach, and acid from entering the intestines
  12. Pericardium
    • A membrane that surrounds the heart and lines the pericardial cavity
    • Contains a lubricating fluid and isolates the heart from body movements such as the expansion and contraction of the nearby pleural (lung) cavity
  13. Diaphragm?
    This dome-shaped muscular wall separates the thoracic from the abdominal cavity. It is also the most important muscle for?breathing,?permitting inhalation and exhalation. Three major vessels pass through the diaphragm between the thorax and the abdomen. These are the?aorta, posterior vena cava,?and theesophagus.
  14. Liver?
    • This dark brown organ dominates the upper abdomen. The?falciform ligament,?a ventral peritoneal membrane attaches the liver to the diaphragm and to the ventral body wall. The?coronary ligament?attaches the dorsal portion of the liver to the central tendon of the diaphragm.
    • The falciform ligament lies in a cleft of the liver which divides it into right and left halves. Five lobes can be differentiated. The four principal lobes may be seen from the ventral aspect, they are the?right lateral, right central, left central?and?left lateral.?A very small lobe, the?caudate lobe,?may be seen when the intestinal coils are moved to the left. It is attached to the posterior surface of the right lateral lobe.
    • Liver: A large organ located above and in front of the stomach. It filters toxins from the blood, and makes bile (which breaks down fats) and some blood proteins.
    • The fetal pig��s liver is large because the liver produces all the fetal blood, including red and white blood cells (the bone marrow takes over blood production only after birth)
  15. Gall Bladder?
    • embedded within a depression in its dorsal surface. This sac-like structure stores bile secreted by the liver and releases it into the duodenum. Bile is transported by the?cystic duct?from the gall bladder. It is joined by the?hepatic duct?from the liver to form the?common bile duct?which enters the duodenum.
    • A small, muscular, sac-like organ located near the duodenum. It stores and releases bile (a digestive chemical which produced in the liver) into the small intestine.
  16. Stomach?
    • This muscular pouch lies on the left side in the upper abdomen. It is the continuation of the esophagus. Find the esophagus and locate where it pierces the diaphragm to join the stomach. This is the?cardiac?end of the stomach. The?fundus?is the dilated anterior portion; the?body?is the main portion, while the?pyloric?region is the most posterior. This end joins the duodenum.
    • The green debris found in the stomach and elsewhere in the digestive tract is called?meconium.?Since the animal is still in the fetal state it does not represent food actually eaten. It is a combination of bile-stained mucus, epithelial cells sloughed off from the skin and lining of the digestive tract, and amniotic fluid swallowed by the fetus. It will be discharged in the first bowel movement of the newborn.
    • A sack like, muscular organ that is attached to the esophagus. Both chemical and mechanical digestion takes place in the stomach, food is churned in a bath of acids and enzymes.
  17. Small?Intestine?
    • the first portion of the small intestine is the?duodenum.?It is a continuation of the pyloric end of the stomach. It is a short ��U�� shaped tube, approximately 1 cm. long. The?common bile duct?and the?pancreatic duct?open into the duodenum. The second section of the small intestine is the?jejunum,?which makes up about half the length of this organ. The?ileum?is the final section. Open the jejunum or ileum, wash its contents and touch the inner surface with your fingertips. The velvety texture felt is due to the presence of numerous?villi?along the inner walls. Use a hand lens or a low power dissection microscope to observe them more clearly.
    • Divided into three sections, duodenum (receives chime from the stomach through the pyloric sphincter, ducts that empty into the duodenum deliver pancreatic juice and bile from the pancreas and liver, respectively). The jejunum is the middle section of the small intestine. The ileum is the last section of the small intestine, with the ileocecal valve connecting to the large intestine.
    • The reason for the length of the small intestine is due to the fact most of the absorption of food occurs in it, therefore there needs to be a higher surface area to volume ratio for maximum absorption.
  18. Large Intestine?
    • Follow the coils of the small intestine. The end of the ileum enters the large intestine. At this juncture the?cecum,?a short blind sac about 2 cm. long, is formed. In some organisms such as horses, this section is enlarged and houses microorganisms which can digest cellulose. Humans possess a?vermiform appendix?that projects from the end of a short cecum. Cut into the cecum at about the point where the ileum enters. Wash out its contents, look for and locate the?ileocecal?valve.
    • The?spiral colon?is a compact coiled mass clearly visible upon the left ventral surface. It is shorter, darker, and thicker than the small intestine. It is the major portion of the large intestine. The posterior dorsal portion of the large intestine is the?rectum.?It descends along the midline through the pelvic girdle to the?onus,?the intestinal opening to the exterior. The colon of human beings is relatively shorter than that of the fetal pig and is not coiled.
    • Cecum is a dead-end pouch at the beginning of the large intestine, just below the ileocecal valve. The appendix is a fingerlike attachment to the cecum that contains lymphoid tissue and serves immunity functions. The colon, representing the greater part of the large intestine, consists of four sections; ascending, transverse, descending and sigmoid colons. The rectum is the lower part of the intestine where feces are stored before excretion. The anal canal opens to the anus. Functions include: defecation, absorption of vitamin b + k & remaining water, bacterial digestion and peristalsis.
  19. Pancreas?
    • Lift the main portion of the small intestine. Expose the stomach and duodenum. Observe the pancreas, a lobulated glandular structure lighter in color than the neighboring intestines. Its main portion lies in the loop of the duodenum. An elongated portion may be observed extending to the left, toward the stomach and spleen. Parts of the gland may also be seen along the dorsal body wall extending to the right of the duodenum and along the dorsal midline. The human pancreas is much more compact. Its duct, the?pancreatic duct,?enters the duodenum. It is small and difficult to find since it is embedded in glandular material.
    • Produces pancreatic amylase for the breakdown of carbohydrates, also an endocrine gland producing insulin and glucagon.
  20. Spleen?
    • this dark-colored elongated organ can readily be seen in the left side of the abdominal cavity without moving any other organs. It lies to the left of the stomach, along its greater curvature, and extends toward the right. It is tied to the stomach by a portion of the?greater omentum,?a specialized fold of the peritoneum, known as the?gastrosplenic ligament.
    • A large, highly vascular lymphoid organ, lying in the human body to the left of the stomach below the diaphragm, serving to store blood, disintegrate old blood cells, filter foreign substances from the blood and produce lymphocytes.
  21. Kidney?
    • this reddish-brown bean-shaped organ lays embedded retroperitoneally, namely, behind the parietal peritoneum, in the dorsal body wall, one on each side. The?adrenal gland?is located near the anterior end of the kidney, but is separated from it, lying slightly media1 of the kidney. In humans the adrenal gland forms a cap upon the kidney.
    • Either one of a pair of the organs in the dorsal region of the vertebrate abdominal cavity, functioning to maintain proper water and electrolyte balance, regulate acid-base concentration and filter the blood of metabolic wastes, which are then excreted as urine.
  22. Urinary?Bladder?
    in the fetal pig the urinary bladder is an elongated sac in the lower ventral abdominal cavity. It lies between the prominent?umbilical arteries?and is seen when the portion of the?body wall supporting the umbilical cord is folded down.
  23. Reproductive Structures?
    Most of the female reproductive structures and some of the males�� are located in the abdominal cavity. The urogenital system and its associated structures will be studied and more fully discussed in a later chapter.
  24. Umbilical cord
    • to transfer nutrients from the mother to the fetus.
    • 2 arteries are together, vein appears thicker
  25. Heart
    • The ribs in the thoracic cavity provide protection and support for the vulnerable lungs and the heart, as they are constantly expanding and contracting. However, in the abdominal cavity, the structures below the diaphragm are much more muscular and requires less protection.
    • In the fetus, there is an opening between the?right?and?left atrium?(the?foramen ovale), and most of the blood flows through this hole directly into the left atrium from the right atrium, thus bypassingpulmonary circulation. The continuation of this blood flow is into the left ventricle, and from there it is?pumped?through the?aorta?into the body. Some of the blood moves from the aorta through theinternal iliac arteries?to the?umbilical arteries, and re-enters the?placenta, where?carbon dioxide?and other waste products from the fetus are taken up and enter the maternal circulation.
    • Heart regulates the circulation of blood to the rest of the body
  26. Lung
    • Texture of the lungs is smooth; it is made up of smooth muscle.
    • Since the lungs of the fetus are not functioning to oxygenate, only a small amount of blood goes there for growth and development. The fetus takes in highly oxygenated blood from the mother via the umbilical vein.
    • Immediately after it is born will a pig first make use of its lungs. In regards to the umbilical cord, the cord will begin to deteriorate as it is no longer needed to transfer oxygen from the mother to the fetus.
    • Gas exchange
  27. Thyroid gland
    • Below the larynx and on top of the trachea
    • production of the hormones
    • used by peripheral organs such as the?liver, kidney?and?spleen
  28. Aorta
    Vena cava
  29. Larynx
    The part of the respiratory tract between the pharynx and the trachea, having walls of cartilage and muscle and containing the vocal cords enveloped in folds of mucous membrane. The larynx is the ��voice box��, functions include; voice production, control of airflow, and swallowing.
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fetal pig dissection questions.txt