Bio 169 Essay

their relation to the above questions. Describe the role of the nervous system, adrenal glands, kidneys and

Consequently, the efferent arteriole, which filters blood away from the glomerulus, is tinier in diameter than the afferent arteriole, which carries blood into each glomerulus. This puts blood under high pressure in the glomerulus; thus it forces tiny molecules and liquid out of the capillary and into the Bowman’s capsule. Soon afterwards, the tiny and liquid molecules cross the epithelium of the Bowman’s capsule, the basement membrane and capillary wall in order to get into the Bowman’s capsule and to arrive in the nephron tubules. The consequence of this is that the filtrate (the tiny and liquid molecules) pass along the remainder of the nephron and helpful substances are reabsorbed along the route. Last of all, “the filtrate flows through the collecting duct and passes out of the kidney along the ureter” as mentioned by (Parson’s, R: p128).

7. Why is most of the blood volume in the veins, and how is blood returned to the heart in this low pressure system?

1. Name the circulatory system that carries blood from the heart to the lungs and back to the heart.

8. What type of membrane does the dialysis tubing represent? Give an example of this type of

Kidneys must process tremendous amounts of blood, which may be up to 4 liters of blood per kilogram every minute in humans. The functional unit of the kidney is the nephron, comprised of the renal tubule and associated vasculature. Major kidney structures are described below.

Because of very high glomerular filtration rates, nearly the entire volume of the blood enters the renal tubules every 30 minutes. Obviously, most of it must be reabsorbed to avoid

In this assignment I will be describing the microstructure of a typical animal cell and the functions of the main cell components. Describing and explaining the factors the ways in which materials move in and out of cells. I will also be analysing the role of the phospholipid bilayer in terms of movement of materials in and out of cells.

Works in conjunction with the blood supply to carry waste products away from the area.

of the water. The osmolality of the water leaving the tube of Henle is lower than the

Your kidneys are two bean-shaped organs, each about the size of your fist. They're located behind your abdominal organs, one on each side of your spine. Like other major organs in the body, the kidneys can sometimes develop cancer. Your kidneys are part of the urinary system, which removes waste and excess fluid and electrolytes from your blood, controls the production of red blood cells, and regulates your blood pressure. Inside each kidney are more than a million small filtering units called nephrons. As blood circulates through your kidneys, the nephrons filter out waste products as well as unneeded minerals and water. This liquid waste — urine — flows through two narrow tubes (ureters) into your bladder, where it's

1.   Compare this data with your baseline data.  How did increasing the afferent arteriole radius affect glomerular filtration rate?

In the human body, the flow of blood through vessels is determined by pressure differentials and vascular resistance. There a number of feedback systems which are responsible for the regulation of arterial pressure, dependent on autonomic nerves and circulating hormones. Moreover, depending on the region of the body the vascular resistance is influenced by; level of sympathetic vasomotor nerves, levels of hormones and local factors including metabolites and endothelial factors. Additionally, resistance is dependent on the length of vessel and inversely with diameter; larger driving force equals faster flow, and increasing resistance hinders flow. The equation below conveys the relationship between pressure, resistance and flow.

These signal messengers will rapidly communicate with the autonomic neural system, in order to decrease sympathetic influence on the heart and blood vessels and increase parasympathetic activity, so that mean arterial blood pressure returns to its normal. By releasing the neurotransmitter acetylcholine (Ach), parasympathetic nerves will decrease the frequency of the action potentials of the sinoatrial (SA) and the atrioventricular (AV) nodes, found in the heart. This mechanism will decrease cardiac output by reducing the number of heart beats and the organ’s force of contractions (Milnor, 1990). Parasympathetic activity will also expand vessels, decreasing their resistance to blood flow and therefore decreasing total peripheral resistance. As veins get wider, they will retain blood causing a reduction in venous return to the heart. Decreased amount of blood in the ventricles at the end of diastole (period between contractions of the heart) will consequently decrease cardiac output and blood pressure (Constanzo, 2012).

The vertebrate kidney is an important organ that serves vital roles in waste excretion, osmoregulation, metabolites reabsorption, maintenance of acid-base balance and even hormone secretion. Nephron is the basic functional unit of a kidney which consists of a blood filter (the glomerulus) and renal tubules that joins to a collecting duct. Nephron filters blood plasma and the filtrate is further modified and refined in the tubules via selective solute reabsorption and secretion. The consequential “unwanted” waste is drained into collecting ducts and excreted (Reilly 2000; Jacobsen, 1981).