Endocrine Glands Regulate
Other Key Body Functions
LEARNING OBJECTIVES
1.
List
the major hormones of the adrenal gland
and explain their effects on the body.
2.
Describe
the influence of the hypothalamus
and pituitary gland on the hormones of the
gonads.
I
n
addition
to
the
hypothalamus/pituitary
gland, thyroid gland, parathyroid gland, and
pancreas, other endocrine glands control sev-
eral body functions, including chemical com-
position and volume of blood, metabolism, contractions of
smooth muscles and heart muscles, reproduction, and dai-
ly rhythms (circadian rhythms). These glands include the
adrenal glands, the gonads (ovaries and testes), and the
pineal gland, along with endocrine cells contained within
other organs. Let’s start with the adrenal glands.
3.
Identify
the hormone secreted by the pineal
gland and its function.
4.
List
the hormones secreted by endocrine cells
not located in endocrine organs and their sub-
sequent effects.
Adrenal Glands Regulate
Many Functions
An adrenal gland sits on top of each of the kidneys (Figure
9.14) . Each gland consists of an outer cortex that surrounds
an inner medulla. The cortex secretes three types of ste-
roid hormones—mineralocorticoids, glucocorticoids, and an-
drogens—each from different layers. The medulla secretes
epinephrine and norepinephrine. Let’s take a closer look at
each of these hormones, their effects, and their secretion.
I
T he stru c tu re o f th e ad ren al g lan d s • Figure 9.1 4
The adrenal glands rest on top of the kidneys. Each gland has two parts (cortex, medulla)
surrounded by a capsule. Cells within each part secrete different hormones.
Kidney
Adrenal
glands
T ,
4
Capsule
Adrenal
cortex
Adrenal
medulla
Right adrenal
gland
Right renal
_
artery
Right renal
vein
Inferior
vena cava
I
ww
a.
Anterior view
b. Section through
left
adrenal
gland
Left adrenal
gland
Left renal
artery
Left renal
vein
Abdominal
aorta
Capsule
Adrenal cortex:
Zona glomerulosa
secretes
mineralocorticoids,
mainly aldosterone
Zona fasciculata
secretes
glucocorticoids,
mainly cortisol
Zona reticularis
secretes androgens
Adrenal medulla
chromaffin
cells secrete
epinephrine and
norepinephrine (NE)
c.
Subdivisions of the
adrenal
gland
Endocrine Glands Regulate Other Key Body Functions
269
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