The Reproductive System 479
As the Body Ages continued
men with BPH require medical treatment. Prostatic cancer is the third leading
cause of cancerous death in males 55 years of age or older. Prostatic cancer also
causes enlargement of the prostate gland, producing difficulty in urination.^
Impotence is the inability of a male to achieve penile erection and, less
frequently, the inability to ejaculate after achieving an erection. Impotence
increases in men between 60 and 80 years of age. Since the fibrous connective
tissue of the penis increases with advanced age, this causes a decrease in the
speed of an erection, occasionally causing impotence in some men. However,^
there is great variation in the sexual activity of older men. Much of this variation can be re-lated to
genetic factors as well as psychological changes that develop over time. Some men remain very
active sexually, while others experience a decrease in their sexual activity and sexual interests.
Body Systems Working
Together to Maintain
Homeostasis:The Reproductive SystemIntegumentary System
●● Pressure receptors in the skin get stimulated during
sexual activity, resulting in sexual pleasure.^
●● Male sex hormones activate the skin’s sebaceous
glands to produce oil for dermal lubrication.^
●● Sex hormones cause the development of pubic and
axillary hair during puberty.^
●● Female sex hormones cause fat to be deposited on
the hips and breasts during puberty.^
●● The skin protects the reproductive organs by being
the first line of defense against microorganisms.
Skeletal System
●● The bones are a source of calcium needed during
lactation, or breastfeeding, of the newborn infant.^
●● The pelvis encloses and protects the reproductive
organs.^
●● The sex hormones cause the development of broad hips
in women and narrow hips and broad shoulders in men.
Muscular System
●● The heart pumps blood to maintain an erection.
●● Smooth muscle contractions of the uterus result in
delivery of the newborn.^
●● Skeletal muscle contractions result in an erection.
●● Male sex hormones cause the development of more
muscle mass in men.
Nervous System
●● The nervous system’s sensory and motor neurons
play a major role in sexual pleasure and activity.^
●● The hypothalamus triggers the onset of puberty.
●● Sex hormones influence the development of the brain in
the fetus.
Endocrine System
●● Estrogens and progesterone control the production
and development of the ova in females and secondary
female sexual characteristics.^
●● Testosterone controls the development of sperm and
the secondary sexual characteristics of males.^
●● Placental hormones maintain pregnancy.Cardiovascular System
●● Blood pressure maintains erections in both men and
women.^
●● Blood transports sex hormones to target organs.
●● Pregnancy results in the heart working harder to
maintain circulation between the mother and the
developing fetus.Lymphatic System
●● The female immune system does not destroy the
male sperm cell, thus ensuring fertilization.^
●● The immune system does not reject the developing fetus.
●● The immune system protects the reproductive organs
from disease.