THE URINARY SYSTEM
(pp. 985 - 989)
I. FUNCTION OF THE URINARY SYSTEM
A. Excretion - Excretion is the elimination of _waste products____ from _metabolism_______.
The urinary system is the body’s main excretory system. When _proteins_______ are
metabolized, a waste product called _urea____ is formed. If urea accumulates in the
blood, it is _toxic_____. Urea is removed from the blood by the _kidneys_______, the
main organ of the urinary system.
B. Homeostasis - The urinary system maintains homeostasis in the body by monitoring the
_composition___, _volume____, and pH of the blood.
II. THE BLOOD WASHING PROCESS
Oxygenated, “dirty” blood on its way to be washed leaves the _left ventricle___ of the heart
by way of the _aorta_______ → _renal artery__ → _kidney_____. Each kidney contains
approximately one million _nephrons____, the “washing machines” of the blood.
A. Blood-Washing
Inside the kidney blood enters a _nephron____ and _urea___ is filtered out of the
blood. Although the blood is now “clean”, its oxygen has been used up by the kidney for
_cellular respiration_____, so it must return to the _heart_____. The clean blood
flows into the _renal veins____ → _vena cava___ → _right atrium______.
B. Elimination of Urine
The “dirt” that has been washed from the blood forms urine, consisting of _urea__ & other
wastes. It is pooled with the urine produced in other _nephrons____, and leaves each
kidney by way of tubes called the _ureters__ → _urinary bladder__ → _urethra___. The
urinary bladder is a muscular sac that collects and stores urine until it is expelled from the
body. When the urinary bladder is approximately _1/3____ full, a message is sent by way of
a _sensory neuron_ to the _cerebrum_____. The urine ultimately leaves the body via the
_urethra_____.
THE ENDOCRINE SYSTEM
(pp. 997 - 1008)
There are two systems that regulate the body. The nervous system relays information to the body using
_electrical impulses__________________ that travel very _quickly______, but the messages are short-lived.
The endocrine system uses _hormones________, or _chemical_______ messages that travel through the
_blood____ to relay information to the body. The endocrine system is slower-acting, but the action of
hormones is __longer-lasting___________. The _hypothalamus__________, which maintains homeostasis
in the body, controls most of the glands of the endocrine system.
I. HORMONES
A. Hormone Production
Most hormones are produced by _endocrine______ glands, secreted into _capillaries______, and
transported by the _circulatory____ system to their destination. The destination is known as the
_target_________. A hormone may have only one target, or it may have several.
B. Control of Hormone Production
Hormone release is regulated by a mechanism known as _negative feedback________.
Information about the effect of the hormone is “fed back” to the gland …. when the desired condition
is reached, the gland _shuts off______________
II. SELECTED GLANDS OF THE ENDOCRINE SYSTEM
Gland
Location
Hormone
Pituitary
Brain
Growth
Hormone
Effect
Stimulates _growth____; undersecretion results in
_dwarfism_______; oversecretion results in
_gigantism_____
Thyroid
Base of Throat
Thyroxine
Regulates _metabolism_______; requires
_iodine____ for normal function
Pancreas
Under Stomach
Insulin
Pancreas
Under Stomach
Glucagon
Adrenal Glands
Above Kidneys
Epinephrine
(also known as
_adrenaline_)
Testes
Scrotum
Testosterone
Ovaries
Either side of
uterus
Estrogen/
Progesterone
_Decreases________ blood _glucose______
concentration by stimulating cells to take up glucose;
triggers storage of glucose as _glycogen_________;
not produced in individuals with _Diabetes mellitus,
Type I________
_Increases________ blood glucose concentration by
breaking down _glycogen______ stored in liver to
glucose
 Known as _”fight-or-flight”____ hormone
 _Bronchioles____ dilate to increase air flow for
__cellular respiration_______
 _Glycogen____ in the liver is broken down to
glucose for _cellular respiration____
 _Heart____ rate is increased
 Blood flow to the _skeletal______ muscles
increases
 Blood flow to the _digestive__ system is
decreased
Triggers development of secondary sex
characteristics; _meiosis____ to produce
_haploid____ sperm cells.
Triggers development of secondary sex
characteristics; __meiosis_____ to produce
_haploid___ egg cells.