Chapter 3: Functioning Systems Flashcards

Question

Ovaries

Answer 1

Hormone produced : Oestrogen Function of Hormone : For maturation of egg cells / reproduction

Answer 2

Digestion consists of 4 main steps: ingestion, digestion, absorption and egestion

Answer 3

1. Food is ingested and broken down physically with the help of teeth (mechanical digestion). While the food is in the mouth the salivary glands release saliva which has enzymes. The enzyme amylase in the saliva breaks down complex carbohydrates to simpler ones and mucin softens the food. The food that is lumpy is now called a bolus. 2. The bolus is swallowed and moves into the oesophagus through muscular contractions called peristalsis. The oesophagus ends at the oesophageal sphincter which connects to the stomach. 3. The bolus then passes into the stomach through the oesophageal sphincter. In the stomach, food is chemically digested by gastric juice. Gastric juice is produced via the sensory cells of the stomach wall. It is made up of mucus, water, hydrochloric acid and the enzyme pepsin. It is highly acidic and has a pH of 1.5 to 3. The bolus is also mechanically digested with the churning action of the stomach. Once the bolus becomes a soupy mixture it is called chyme. 4. At the end of the stomach is the pyloric sphincter. Chyme passes through the pyloric sphincter and arrives at the duodenum (the first part of the small intestine). 5. The pancreas secretes pancreatic juices which consist of the enzymes amylase, trypsin and lipase as well as bicarbonate. The bicarbonate neutralises the acidity in the duodenum. The duodenum has an alkaline pH at 7-8.5. 6. At the same time the gallbladder releases stored bile into the duodenum to break down fat. Bile mechanically breaks down fat into fatty acid and glycerol through a process called emulsification. (Bile is produced by the liver). 7. The food then moves into the ileum of the small intestine. Most absorption takes place here through tiny finger-like projections called villi. The nutrients move into the villi and then into the bloodstream (to get to our cells) as the villi is surrounded by capillaries. 8. The remaining waste moves into the colon (large intestine). Here water and salts are absorbed back into the bloodstream. 9. What's left over is solid waste (faeces). The faeces pass into the rectum and once ready exit the body via the anal sphincter at the anus. This is called egestion.

Answer 4

The kidneys remove metabolic waste and regulate the concentration of bodily fluids. This is done by adjusting the amount of water reabsorbed back into the tubules and the amount of salt secreted in the urine.

Answer 5

is the functional unit of the kidney. Filtration of the blood takes place here.

Answer 6

- The blood enters the kidney via the renal artery and into the cortex/medulla of the kidney where the nephrons are - The blood then enters the nephron through the afferent arteriole into the glomerulus - The glomerulus filters the blood. The clean blood exits the glomerulus via the efferent arteriole - The waste produced via the filtration of the glomerulus is the glomerular filtrate. - Glomerular filtration is the first step in making urine. It is the process that your kidneys use to filter excess fluid and waste products out of the blood into the urine collecting tubules of the kidney, so they may be eliminated from your body. - The glomerular filtrate then passes through the proximal convoluted tubule where reabsorption starts (mainly of ions) - The filtrate then moves into the loop of Henle where reabsorption of water takes place. - Antidiuretic hormone (ADH) stimulates the reabsorption of water at the loop of Henle along with counter current systems consisting of ions that draw water in (via osmosis) and promote reabsorption. - It then moves into the distal convoluted tubule where final reabsorption takes place then makes its way into the collecting duct to be released into the kidney to exit via the ureter as urine which gets collected in the bladder. The urine is then excreted via the urethra