Chap. 50 The Circulatory System Pt. 2

Front 1

Portal system
What?
Purpose?

Back 1

• When one capillary bed feeds into another through a vein or artery, rather than that blood vessel passing through the heart first

• Transports products in high concentrations, whereas if the heart were involved, those products would be spread throughout the entire body

Front 2

Hepatic portal system
Hepatic = ?

Back 2

Hepatic = liver

Sends digested and absorbed nutrients from the capillaries of the intestines, to the hepatic portal vein, to the hepatic capillaries, and into the hepatocytes (liver cells)

Intestinal capillaries --> hepatic portal vein --> hepatic capillaries

Front 3

Renal portal system
Renal = ?

Back 3

Renal = kidney

Blood flows from the glomerulus to the efferent arteriole, and out to the peritubular capillaries

Glomerulus --> efferent arteriole --> peritubular capillaries

Front 4

Nephron tubule

Back 4

Involved in filtration and selective reabsorption within the kidney

Front 5

Parts of the nephron
9

Back 5

1) Afferent arteriole = feeds into the glomerulus from the renal artery
2) Efferent arteriole = comes out of the glomerulus to the peritubular capillaries
3) Glomerulus = capillary ball within the Bowman's capsule
4) Bowman's capsule = holds glomerulus, first part of nephron
5) Peritubular capillaries = surround the tubules
6) Proximal tubule = involved in absorption
7) Loop of Henle = nephron's dip
8) Distal tubule = involved in secretion
9) Collecting duct = fluid drains out of nephron

Front 6

Vessel histology
3

Back 6

1) Tunica intima = innermost layer, composed of endothelial cells
2) Tunica media = middle layer; composed of smooth muscle
3) Tunica adventitia (externa) = outermost layer; composed of connective tissue

Front 7

What is the importance of arterial blood pressure?

What are the 2 mechanisms?

Back 7

To ensure that the pressure is high enough to pump the blood to all the organs of the body

1) Vasoconstriction
2) Maintaining fluid volume

Front 8

Adrenal glad
Where
2 layers
Type of tissue in each layer

Back 8

Endocrine gland that sits on top of the kidneys

1) Adrenal cortex = outer layer; glandular tissue which secretes hormones
2) Adrenal medulla = inner layer; nervous tissue which secretes epinephrine (adrenaline)

Front 9

How does vasoconstriction occur from the adrenal medulla?

Back 9

• When blood pressure drops, the adrenal medulla secretes adrenaline, causing the tunica media of the arteries to constrict
• volume decreases, so pressure increases

Front 10

What are baroreceptors?
What is the baroreceptor that lines the afferent renal arteriole?

Back 10

Cells that sense changes in blood pressure

Juxtaglomerular cells

Front 11

How does vasoconstriction occur from the kidney?
5 steps

5 products

Back 11

1) When blood pressure drops, juxtaglomerular cells secrete renin → a hormone that acts like an enzyme
2) A blood protein, angiotensinogen, enters renin and is activated to become angiotensin I
3) Angiotensin I circulates to the lungs and enters the enzyme "angiotensin converting enzyme" (ACE) and produces angiotensin II → a powerful vasoconstrictor!
4) Angiotensin II targets smooth muscle of arteries and stimulates release of aldosterone → steroid hormone
5) This makes you thirsty! Drinking increases fluid volume, increasing blood pressure

1) Renin
2) Angiotensinogen
3) Angiotensin I
4) Angiotensin II
5) Aldosterone

Front 12

What 2 medications are effective for lowering blood pressure?
Why?

Back 12

Renin or ACE inhibitors

Inhibit production of angiotensin II and the release of aldosterone

Front 13

How is fluid volume maintained from the adrenal cortex?

Back 13

1) When blood pressure and sodium ions (Na+) are low the adrenal cortex secretes aldosterone
2) Aldosterone targets the nephron's distal tubule to secrete Na+ into the blood stream
3) Water will follow the solute! H2O enters the blood stream, raising volume and blood pressure

Front 14

What is the hypothalamus?

How is fluid volume maintained from it?

Back 14

Hypothalamus = part of the brain which secretes the hormone "Antidiuretic hormone" (ADH) AKA "vasopressin"

1) When blood pressure drops, ADH is secreted from the hypothalamus into the blood stream
2) ADH targets the distal tubule and collecting duct of the kidney to synthesize more aquaporins for reabsorption of water into the blood
3) This increases fluid volume, increasing blood pressure