Nervous System

We felt the skull until we reached the base and made an incision horizontally. We thinly cut around the head exposing the cranium. We removed the temporalis and muscles of the occipital region. We carefully cut cartilage of the lambdoidal ridge are the top of the cranium. My partner and I gently removed the brain.

 

We observed the brain and pointed out the cerebrum, cerebellum, medulla oblongada, and spinal cord. The line splicing the brain into two hemispheres is the longitudinal fissure.

This is a segment of the cervical enlargement and attached to the ends are spinal nerves.

Circulatory and Respiratory

 The next day we hit the respiratory and circulatory systems. We cut from the abdomen cavity into the thoracic cavity and found it heavy in fascia. When we opened the rib cage we cut through muscle and connective tissue. We located the larynx which followed by the trachea, (ridged and bumpy appearance) leading to the thyroid gland which is surrounded by the thymus. Attached to the thymus and thyroid gland is the cranial vena cava which leads to the heart and lungs. The heart lies in the pericardial cavity, the red areas are arteries and the blue areas are veins. We gently cut the pericardial sac which is a tough membrane composed of two coelomic epithelial linings, the parietal pericardium and the parietal pleura to expose the heart.  We traveled down to the lungs by following the trachea all the way down. The trachea branched into bronchi which lead to the right and left lobe of the lungs. We observed that the bronchi branch into smaller bronchi called bronchioles. Bronchioles branch into alveoli was so small you cannot see it through the naked eye. Its where the exchange of oxygen and carbon dioxide take place. 

In this picture you can see the cranial vena cava on top and to the right the aorta. Directly beneath the cranial vena cava lies the right atrium and below the right ventricle. The pale pink line towards the bottom is the coronary artery and vein. Opposite of the right atrium is the left atrium and below the left ventricle.

Digestive, Excretory, and Reproductive Systems

The second part of our dissection by opening the entire abdomen cavity slicing the parietal peritoneum. We located the umbilical vein, cut it, and tied it with a string. We made are way one by one towards each organ and removed the coelomic epithelium tissue covering it in this cavity known as visceral peritoneum.

The duodenum is the first part of the small intestine, the jejunum is the middle section and the ileum is the final section. The caecum is the first part of the large intestine which forms a pouch to the ileum and colon. Small intestine absorbs food nutrients through finger like villa(picture of villa at end of post) and large intestine stores waste products for elimination. The large intestine includes the colon (transverse,descending and ascending) and the rectum. 

If you follow the umbilical vein you can find the urinary bladder. It is located between the two umbilical arteries. If you pull on the umbilical cord you can locate the urethra, a single tube exiting the urinary bladder. The urethra leads to the penis, it is a tube in the penis. When we pulled again on the umbilical cord after we discovered the urethra and on the dorsal side of it we spotted the seminal vesicles. 

Sperm travel : Testes => Epididymis => (mature and stored) => (ejaculation) => Ductus Deferens => Urethra => Penis

Kidney- functions in removing waste products and regulating the water fluid levels. Contains three major regions: the cortex, the medulla, and the pelvis. 

Pancreas-breaks down proteins, carbohydrates, and fats using digestive juices, secretes hormones that affect the level of sugar in the blood, and produce chemicals that neutralize stomach acids that pass from the stomach into the small intestine. 

The liver contains the left and right median lobe of liver. It's the largest gland producing bile which facilitates the process of digestion and the emulsification of lipids. Located in the pelvic region of the abdomen below the diaphragm and the ribs. The gallbladder is a storage tank for bile produced by the liver. It is located behind the liver to the right side of the rib cage. 

Stomach-breaks down food, stomach acid and enzymes help kill bacteria and infectious organisms. By opening the stomach you can see the longtiudinal ridges lining the wall called gastric rugae by cutting along the greater curvature and releasing all of the fluids in it.  We opened up the stomach Cardiac sphincter is located at the top of the stomach stopping food from going back up into the esophagus. Pyloric sphincter is at bottom of the stomach, it stops bile and digested food from entering the stomach.

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Spleen-removes erythrocytes from blood supply and removes, stores, and produces lymphocytes. Its found in the upper left portion of the abdomen between the stomach and diaphragm underneath the rib cage. Composed of two tissues, white and red pulp. Mammals are the only species with diaphragms.

Villi and microvilli in the small intestine-increase surface area for a faster absorption rate of nutrients.

Jaw

The first portion of the day resulted in breaking the mandible and cutting the mouth laterally towards the pinna. We distinguished the hard plate from the soft plate located on the upper jaw and felt the incisors and canine teeth, although they were under developed they were still sharp. The first hole is the opening to the glottis and posterior is the epiglottis. The epiglottis is a flap of connective tissue that is made of elastic cartilage at the base of the tongue. It covers the opening of the trachea to close the laryngeal inlet during swallowing, preventing food from entering the lungs.

External Anatomy

The first day of our pig dissection was mainly focused on observing the external anatomy, no slicing or cutting was involved during the first part of the day. The immediate reflects my partner and I discovered was its pale moist skin. It has all of its limbs attached with four digits with hoofs on each hands and feet. The fetal pig's epidermis was its fine, white, short hair. In the abdomen, the part of the trunk between thorax and the perineum was its teats parallel to one another. Between the teats lies the umbilical cord and at the end of it was the urogential opening. The scrotum identified the sex of the pig, male. The second part involved cutting a thin layer of the marginal papillae from the tongue and viewing it under the microscope.