Internal Organs of Mammals

Functions of the Liver

1. Produces bile and emulsifies fats 2. Makes and stores glycogen- also stored in muscles; also stores fats, minerals, and vitamins(A, B12, D, E, And K) 3. Nutrient Interconversion- Can convert some nutrients into others; can transform substances to those usable by cells. 4. Detoxification 5. Phagocytosis- Hepatic phagocytic cells (Kuppffer cells) destroys old red and white blood cells, some bacteria, and other debris. 6. Synthesis- produces plasma (albumin, fibrinogen, and globulins), heparin, and clotting factors.

Greater Omentum

A long double fold of connective tissue that extends from the stomach over the surface of the small intestine; can accumulate quite a bit of fat

Large Intestine

Also known as the colon. The cecum is the blind sac extending below the ileocecal junction, where the small intestine joins the large intestine. This is where the appendix is found in humans.The colon is 1.5 to 1.8 m long and consists of four parts: ascending colon, transverse colon, descending colon, and sigmoid colon. It takes 18-24 hours for material to pass through the large intestine. The colon reabsorbs water.

Trachea

Cartilaginous tube from the pharynx to the lungs; held open by the rings of cartilage; branches into the bronchi and bronchioles.

Mesentery

Connective tissue between the folds of the small intestine to hold it in place; rich in blood vessels to aid in absorption.

Small Intestine

Consists of three parts: Duodenum, closest to the stomach; the jejunum, middle part; ileum last part. 12-18 feet long. This is where the greatest amount of digestion and absorption takes place. The inner lining of the small intestine feels like velvet because of the tiny projections called villi that increase the surface area.

Diaphragm

Dome-shaped muscle separating the thoracic cavity from the abdominal cavity; primary muscle of respiration.

Esophagus

Flattened, slightly muscular tube leading from the pharynx to the stomach; a little less than 8 inches.

Heart

Found in the mediastinum, the central cavity within the thoracic cavity; surrounded by the double-layered pericardium. The heart consists of four chambers: two atria, non-muscular upper chambers, and two ventricles, muscular lower chambers.

Stomach

Gastroesophageal opening surrounded by the cardiac sphincter; Fundus is the part of the stomach superior to this opening; the cardiac part is the upper part of the stomach, the body is the middle, and the bottom is the pyloric part. The pyloric sphincter surrounds the opening to the small intestine. Large folds called rugae are found in the inside wall of the stomach, allowing the stomach to stretch as it fills. The stomach is primarily a storage and mixing chamber(2-4 hours). Chyme is the term for the mixture of ingested food and stomach secretions, which include mucus, hydrochloric acid, gastrin(increases gastric secretions and causes a minor increase in gastric mobility), histamine, intrinsic factor( a glycoprotein that binds with vitamin B12, making the vitamin more readily absorbed in the ileum), and pepsinogen (precursor to the enzyme pepsin, which helps digest protein).

Pancreas

Gland located behind and the below the stomach; both an exocrine and an endocrine gland. Exocrine portion- secretes bicarbonate ions, digest proteins, digest starches, and digests fats into the small intestine. Endocrine portion- islets of Langerhans produce insulin and glucagon to regulate sugar metabolism.

Liver

Largest internal organ of the body

Spleen

Located on the left side in the extreme, superior part of the abdominal cavity. The spleen destroys defective red blood cells; detects and responds to foreign substances in the blood, stimulating an immune response; and acts as a blood reservoir.

Lungs

Passive. Principal organs of respiration; the right lung is larger than the left with three lobes; the left only has two. Consists of air sacs called alveoli which are surrounded by capillaries enabling the exchange of oxygen and carbon dioxide.

Urinary Bladder

Stores urine until it is excreted.

Ureters

Tubes leading from the kidney to the urinary bladder.

Gall Bladder

Usually greenish sac-like structure inferior to the liver; stores bile.

Kidneys

With an outer portion, the cortex, and an inner portion, the medulla. The kidneys filter the blood. Located on small back each other side of spinal.