This is the second to the last post before the end of my sharing about the human anatomy and physiology. Be sure to return for the last post to finish everything. So for today, let us discuss the digestive and urinary systems.
Every cell in the body needs nutrients, yet most cells cannot leave their position in the body and travel to a food source. Therefore, the digestive system must deliver the food to them. The Digestive System with the help of the circulatory system, is the gigantic “meals on wheels,” serving over 100 trillion customers the nutrients they need. It also has its own quality control and waste disposal methods.
Its functions are:
Every cell in the body needs nutrients, yet most cells cannot leave their position in the body and travel to a food source. Therefore, the digestive system must deliver the food to them. The Digestive System with the help of the circulatory system, is the gigantic “meals on wheels,” serving over 100 trillion customers the nutrients they need. It also has its own quality control and waste disposal methods.
Its functions are:
- Ingestion of Food
- Digestion of Food
- Absorption of Nutrients
- Elimination of Wastes
The peritoneum is a serous membrane that lines the abdominal cavity and covers the organs. Mesenteries are double layers of peritoneum that extend from the body wall to many of the abdominal organs. Retroperitoneal organs are located behind the parietal peritoneum.
The oral cavity (mouth) is the first part of the digestive tract, bound by the lips and cheeks, and contains the teeth and the tongue.
Teeth
Salivary Glands
Saliva helps protect the mouth from oral bacteria, starts starch digestion, and provides lubrication.
Here are other digestive secretions and their functions.
Here are other digestive secretions and their functions.
Mastication is accomplished by teeth which cut, tear, and crush the food.
Swallowing (Deglutition)
Swallowing (Deglutition)
Peristalsis is the muscular contraction of the esophagus.
Stomach
Function of the Major Digestive System Hormones
Regulation of Stomach Secretions
Movement in the Stomach
Small Intestine
The mucosa of the small intestine is simple columnar epithelium with four major cell types:
The mucosa of the small intestine is simple columnar epithelium with four major cell types:
- Absorptive cells
- Goblet cells
- Granular cells
- Endocrine cells
Secretions of the Small Intestine
Mucus protects against digestive enzymes and stomach acids. Chemical or tactile stimulation, vagal stimulation, and secretin stimulate intestinal secretion.
Movement in the Small Intestine
Peristaltic contractions occur over the length of the intestine and propel chyme through the intestine. Segmental contractions occur over short distances and mix the intestinal contents.
Mucus protects against digestive enzymes and stomach acids. Chemical or tactile stimulation, vagal stimulation, and secretin stimulate intestinal secretion.
Movement in the Small Intestine
Peristaltic contractions occur over the length of the intestine and propel chyme through the intestine. Segmental contractions occur over short distances and mix the intestinal contents.
The major function of the small intestine is absorption and most of it occurs in the duodenum and jejunum.
Liver
Liver
Functions of the Liver
Panacreas
Functions of the Pancreas
The pancreas produces HCO₃- and digestive enzymes. Acidic chyme stimulates the release of watery bicarbonate solution that neutralizes acidic chyme. Fatty acids and amino acids in the duodenum stimulate the release of pancreatic enzymes.
The pancreas produces HCO₃- and digestive enzymes. Acidic chyme stimulates the release of watery bicarbonate solution that neutralizes acidic chyme. Fatty acids and amino acids in the duodenum stimulate the release of pancreatic enzymes.
Large Intestine
Functions of the Large Intestine
The functions of the large intestine are feces production and water absorptions. Mass movements occur three to four times a day. Defecation is the elimination of feces. Reflex activity moves feces through the internal anal sphincter. Voluntary activity regulates movement through the external and sphincter.
Digestion, Absorption, and Transport
Digestion is the breakdown of food to molecules that are small enough to be absorbed into the circulation. Mechanical Digestion breaks large food particles into small ones. Chemical Digestion involves the breaking of covalent chemical bonds in organic molecules by digestive enzymes.
Absorption begins in the stomach, where some small, lipid-soluble molecules, such as alcohol and aspirin, can diffuse through the stomach epithelium into the circulation. Most absorption occurs in the duodenum and jejunum, although some occurs in the ileum. Some molecules can diffuse through the intestinal wall, whereas others must be transported across the intestinal walls.
Transport requires carrier molecules and includes facilitated diffusion, cotransport, and active transport. Cotransport and active transport require energy to move the transported molecules across the intestinal wall.
The functions of the large intestine are feces production and water absorptions. Mass movements occur three to four times a day. Defecation is the elimination of feces. Reflex activity moves feces through the internal anal sphincter. Voluntary activity regulates movement through the external and sphincter.
Digestion, Absorption, and Transport
Digestion is the breakdown of food to molecules that are small enough to be absorbed into the circulation. Mechanical Digestion breaks large food particles into small ones. Chemical Digestion involves the breaking of covalent chemical bonds in organic molecules by digestive enzymes.
Absorption begins in the stomach, where some small, lipid-soluble molecules, such as alcohol and aspirin, can diffuse through the stomach epithelium into the circulation. Most absorption occurs in the duodenum and jejunum, although some occurs in the ileum. Some molecules can diffuse through the intestinal wall, whereas others must be transported across the intestinal walls.
Transport requires carrier molecules and includes facilitated diffusion, cotransport, and active transport. Cotransport and active transport require energy to move the transported molecules across the intestinal wall.
Some diseases and disorders associated with Digestive System
Now let's move on with the urinary system.
The Urinary System consists of two kidneys, two ureters, the urinary bladder, and the urethra. A large volume of blood flows through the kidneys, which remove substances from the blood to form urine. The urine consists of excess water and ions, metabolic wastes, and toxic substances. The urine formed in the kidneys will flow through the ureters to the urinary bladder, where it is stored until it is eliminated through the urethra.
The Urinary System consists of two kidneys, two ureters, the urinary bladder, and the urethra. A large volume of blood flows through the kidneys, which remove substances from the blood to form urine. The urine consists of excess water and ions, metabolic wastes, and toxic substances. The urine formed in the kidneys will flow through the ureters to the urinary bladder, where it is stored until it is eliminated through the urethra.
Its functions are:
Kidneys
- Excretion
- Regulation of blood volume and pressure
- Regulation of the concentration of solutes in the blood
- Regulation of extracellular fluid pH
- Regulation of red blood cell synthesis
- Regulation on Vitamin D synthesis
Kidneys
The ureters are small tubes that carry urine from the renal pelvis of the kidney to the urinary bladder.The urinary bladder is a hollow, muscular container that lies in the pelvic cavity just posterior to the pubic symphysis. it stores urine. The urethra is the tube that carries urine from the urinary bladder to the outside of the body.
The Micturition Reflex is activated by stretch of the urinary bladder wall. The process is explained more in the picture.
Regulation of Acid-Base Balance
Some diseases and disorders in the urinary system.
This is the end for this post. Don't forget to leave your comments and suggestions. The next post that I will have is the last post for the subject. Be sure to come back to finish everything and to complete the systems of the body.