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Upper Gastrointestinal Tract

The Human Skeleton
Latest Courses Computer Science Improvement in the endometrium may allow for better classification at a later date. Occasionally, microorganisms causing a pyometra may not be detected on aerobic culture, because products of the inflammatory reaction prohibit their growth. It is suspended in the pelvic canal by the broad ligament, which is attached dorsally to the sublumbar region. Share and display models. These are some of the packets that are included in our Human Body Bundle. The character of the cervix reflects the hormonal status of the mare.

Learning Objectives

Digestive System Hands-On Activities – Esophagus, Stomach, Small Intestines

During anestrus, ovarian steroid serum concentrations are low, and the cervix is either short, thin, and open or closed but readily opened. After the first ovulation of the season and during subsequent periods of diestrus, serum progesterone concentrations are increased and the cervix is closed, with a long cylindrical shape.

During estrus, serum progesterone concentrations are low, and estrogen concentrations are high; the cervix is relaxed and edematous.

Visual speculum vaginal examination will allow further assessment of the character of the cervix. Urine in the vagina urovagina may be seen sporadically or be a chronic problem.

Mares with urovagina may have an abnormal voiding pattern, and the endometrium may show histologic evidence of chronic irritation. The neck of the bladder can be used to indicate the caudal boundary of the vagina during ultrasonography.

The vagina can be imaged dorsal to the bladder and examined for any accumulation of echogenic fluid caudal to the cervix. A definitive diagnosis of urovagina requires direct observation of urine in the vagina via vaginoscopy.

Before an endometrial swab is taken, the nonpregnant status of the mare must be confirmed because the swabbing could lead to termination of a pregnancy see Pregnancy Determination in Horses. The perineum is cleansed with povidone-iodine scrub, rinsed, and dried.

The operator dons a sterile sleeve or clean examination sleeve with the hand encased in a sterile glove. A water-soluble lubricant free of bacteriostatic chemicals is placed on the back of the hand and lower arm. When obtaining an endometrial swab sample, the vestibule, vagina, and cervix must be passed. Care must be taken to avoid contamination of the swab by microorganisms in the structures caudal to the uterus that would hinder accurate interpretation of the culture results.

A double-guarded occluded uterine swab is gently guided through the cranial end of the cervix. Once inside the uterine body, the inner guard is advanced from the outer guard, and the swab is exposed to the uterine lumen for 30—60 sec.

The swab tip is withdrawn into the inner guard, which is then withdrawn into the outer guard before the entire swabbing instrument is removed from the uterine body.

The swab tip is carefully placed into a transport system, which is vital to maintain viability of the organisms from the time of sample collection until aerobic culture in the laboratory.

Stuart's carrier medium may maintain microorganisms for as long as 72 hr if stored at ambient temperature. A second endometrial sample may be taken immediately after the first or simultaneously with a uterine swab or cytology brush.

This sample is then evaluated cytologically by rolling it onto a glass microscope slide, fixing and staining with a Romanowsky-type stain, and viewing it microscopically for evidence of neutrophils, debris, and microorganisms. A low-volume uterine lavage can be performed in mares with negative culture results despite obvious clinical signs of endometritis.

Sterile saline 60— mL is infused into the uterus using a closed system with a small uterine catheter. Oxytocin 20 IU, IV is administered to enhance uterine evacuation.

The effluent is collected by gravity flow into a sterile centrifuge tube and then centrifuged. The pellet is then swabbed, placed into transport media, and submitted for aerobic culture. A second swab can be made of the pellet for cytologic examination after staining. In most cases, the mixed growth of a few miscellaneous microorganisms is not significant. A heavy growth of any microorganism should be considered significant unless obvious contamination has occurred. Clinical signs must be correlated with culture results to determine clinical significance and to develop a therapeutic plan.

Isolation of an organism transmitted venereally, such as Taylorella equigenitalis requires a special culture system and certain strains of Pseudomonas and Klebsiella spp, is considered a significant finding. Occasionally, microorganisms causing a pyometra may not be detected on aerobic culture, because products of the inflammatory reaction prohibit their growth.

Aerobic culture results of the endometrial swab should be used as a diagnostic adjunct and not as the sole determinant in diagnosing a uterine infection. A positive culture result must be accompanied by evidence of inflammation for the diagnosis of endometritis to be made. Mares exhibiting clinical signs of infection uterine fluid as seen on ultrasonographic examination per rectum, tail matting or uterine discharge, and the presence of inflammatory cells seen on a stained smear from a uterine sample with a positive endometrial swab are likely to have endometritis.

Inflammation seen on histologic evaluation of the endometrium confirms the diagnosis of endometritis. In these cases, the culture results are useful in determining the sensitivity of the causative microorganism and developing an antimicrobial treatment plan. The following antibiotics see Table: Intrauterine Antibiotics for Use in Mares have been used for daily 3—7 days uterine infusion by diluting with sterile saline to an infusion volume of 60— mL.

Systemic administration of antibiotics may be considered if the microorganism, management situation, and ease of treatment indicate. Two doses of long-acting ceftiofur crystalline free acid 6. Gentamicin sulfate diluted with 20 mL sodium bicarbonate and 20 mL saline. An endometrial biopsy sample is usually obtained immediately after the endometrial samples have been procured. It should be kept in mind that manipulation of the endometrium can quickly cause a neutrophilic response in the endometrium.

Preparation for biopsy is the same as for taking a swab see above. The basket of the biopsy instrument should be kept closed during positioning to prevent accidental procurement of vagina, cervix, or examination glove. As a member, you'll also get unlimited access to over 75, lessons in math, English, science, history, and more. Plus, get practice tests, quizzes, and personalized coaching to help you succeed.

Login here for access. Log in or sign up to add this lesson to a Custom Course. Login or Sign up. All is calm in the rainforest. A beautiful butterfly lands on a flower in search of nectar, but unbeknownst to the butterfly, a well-concealed predator is only inches away. In a fraction of a second, the chameleon strikes out with its tongue, snatching the butterfly from the flower and drawing it into its mouth. The chameleon begins to chew - wait, chameleons don't chew!

But little boys like Timmy, who pretend to be chameleons, do. As Timmy chewed the butterfly and physically broke it down into smaller pieces, his salivary glands went to work, releasing saliva containing amylase - a digestive enzyme that breaks large polysaccharides into smaller ones. Amylase is capable of breaking every other bond between sugars in a polysaccharide.

Between chewing which physically breaks the butterfly into smaller pieces and creates greater surface area for enzymes to contact and amylase which begins breaking complex carbohydrates down into smaller polysaccharides , the digestion of the butterfly has already begun. The tongue then forms the chewed-up and saliva-soaked food into a ball and directs it to the back of the mouth. Here, it enters the pharynx which you may remember is the junction of the mouth and nasal airways that leads down the throat.

However, unlike the air that passes through the larynx on its way to the trachea and lungs, the food must enter the esophagus the tube that serves as a passage for food from the pharynx to the stomach. When Timmy swallows, his larynx moves up, and at the same time, a flap called the epiglottis , flips downward to cover the larynx.

This prevents the food from continuing down the airway. Instead, the food is directed into the esophagus, where muscle contractions push the food down into the stomach. The stomach is a fairly large organ with an elastic wall. It is capable of stretching to make room for over a half-gallon of food and fluid in the average person.

The stomach wall is lined by a layer of epithelial cells and has lots of deep pits that lead to the gastric glands. The epithelial cells inside these glands secrete the different components of gastric juice.

This juice liquefies food and continue the process of chemically breaking it down into smaller components so it can be absorbed by the body. One major component of gastric juice is hydrochloric acid , which you may remember is a very strong acid. It can be represented by the abbreviation HCl. Because of its acidic properties, HCl kills most bacteria found in food.

It also dissolves most types of tissues that we eat into a liquid form that is much more accessible to digestive enzymes. Unfortunately, HCl inactivates amylase, which leaves the polysaccharides only partially digested.

Speaking of digestive enzymes, another major component of gastric juice is pepsin. Pepsin is a digestive enzyme that breaks proteins down into smaller peptides. You can remember the function of pepsin if you remember that pepsin breaks proteins into peptides. But this function of pepsin raises a fundamental question: The answer is that the cell makes an inactive form of pepsin named pepsinogen , which is several amino acids longer than active pepsin.

The extra amino acids block the active site of pepsin, causing it to be inactive inside the cell where it can damage other proteins. However, the HCl in the gastric juice removes these amino acids and converts the inactive pepsinogen into active pepsin once it is out of the cell and inside the stomach.

To keep them from digesting components of the secretory cells, most digestive enzymes are produced in an inactive form known as a zymogen an inactive precursor of an enzyme which requires a change to be activated. In this case, pepsinogen is a zymogen that is activated by HCl and turned into active pepsin. Get access risk-free for 30 days, just create an account. So why doesn't the pepsin and hydrochloric acid digest the epithelial cells that line the stomach?

It turns out that most of the epithelial cells of the stomach secrete large amounts of mucus, which forms a barrier to protect the cells against the acid and pepsin.

In addition, the stomach isn't always filled with gastric juice. Between meals, the stomach is empty and pretty much inactive. However, when a person sees, smells or otherwise anticipates eating food, the brain sends a signal to the stomach to start preparing for a meal. As a result of this signal, the epithelial cells secrete a small amount of HCl into the stomach.

The smooth muscles of the stomach are also activated and start churning the stomach at a low rate. This churning of the stomach, without food in it, is what causes your stomach to growl when it's getting close to meal time. When food enters the stomach, it activates the full response. The epithelial cells secrete lots of gastric juice and the smooth muscles of the stomach are fully activated - causing the stomach to churn and thoroughly mix the food and gastric juice until it is liquefied.

The stomach then releases its liquefied contents into the small intestine a little at a time through the pyloric sphincter the muscular valve at the bottom of the stomach that controls the flow of partially digested food into the small intestine. It takes about 2 to 6 hours for the stomach to completely empty its contents into the small intestine.

During that time, the churning motion and release of gastric juice by the stomach is ramped down until the stomach is empty and - essentially - powered-down. That is, until it receives the next signal from the brain to start powering-up again. As soon as you put a piece of food in your mouth, your body starts the digestive process.

Salivary glands release saliva that contains amylase , a digestive enzyme found in saliva that breaks large polysaccharides into smaller polysaccharides. Chewing begins the physical process of breaking large chunks of food into smaller pieces. The food is swallowed and directed by the epiglottis down the esophagus the tube that serves as a passage for food from the pharynx to the stomach. The epithelial cells of the stomach secrete three major products: Pepsinogen is a zymogen , which is an inactive precursor of an enzyme that requires a change to be activated.

HCl converts it to the active enzyme pepsin , which is a digestive enzyme that breaks proteins down into smaller peptides. Together, pepsin and hydrochloric acid are the major components of gastric juice, which essentially liquefies food and continues to break it down into smaller components.

However, when a person sees, smells, or otherwise anticipates eating food, the brain sends a signal to the stomach to start preparing for a meal. As a result of this signal, the epithelial cells secrete a small amount of hydrochloric acid into the stomach. Smooth muscle is also activated and starts churning the stomach at a low rate.

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