Introduction to human diseases

1. Introduction to Human Diseases
Dr. E. Okon, MD, MRCS(Ed)

2. Atherosclerosis
● Disease characterized by lipid, calcium, and
fibrous deposits in the intima of large and
medium sized arteries, which occlude the
vessels and result in diminished blood supply to
the down-stream tissues.
● Most common cause of death and morbidity in
the United States.
● Arteries to the heart and brain are the two most
important sites of atherosclerosis.

3. ● Myocardial infarcts (“heart attacks”) secondary to
atherosclerosis in the arteries supplying the heart
muscle are the leading cause of death, and cerebral
infarcts (strokes) resulting from atherosclerosis of
vessels supplying the brain are the fifth most
common cause of death in the United States.
● Atherosclerosis of the arteries of the legs and of the
main artery to the intestines (superior mesenteric
artery).

4. Genetic/Developmental Diseases
● Angiomas
– Hemangiomas are local proliferations of capillaries
that may be present at birth. They are common in
the skin, where they vary from small red dots to
large cosmetically distracting “port wine stains”.
– The dilated vessels fill with blood, they are red to
blue and blanch under the pressure of a finger as
the blood is pushed out of them.

5. ● Lymphangiomas, dilated masses of lymphatics,
are much less common. When they occur in the
neck of an infant (cystic hygroma), they may be
frightening in appearance but they usually
regress with age.

8. Inflammatory/Degenerative
Diseases
● Arteriosclerosis means “hardening of the arteries” and is the
generic term used to refer to three different processes: thickening
of the intima and media of small arterioles (arteriolosclerosisor
arteriolar sclerosis), calcification of the media of large arteries
(medial sclerosis or medial calcification), and plaque formation in
the intima of large arteries (atherosclerosis).
● Arteriolosclerosis occurs in response to prolonged hypertension.
It is seen most commonly in the renal arterioles and may
contribute to decreased renal function.
● Medial calcification occurs in the medium to large arteries of the
thyroid, brain, genital tract, and limbs with aging and is not
considered to be a cause of significant disease.

10. Atherosclerosis
● Atherosclerosis is a degenerative condition
● The basic lesion of atherosclerosis deposition of
fibrous tissue and lipids) in the intima of blood vessels,
particularly in the major muscular arteries.
● The earliest visible lesions, called fatty streaks
because they are composed almost entirely of lipid,
can be found even in children dying of unrelated
diseases, and most people older than the age of 30
years have these early, grossly visible atherosclerotic
lesions in their larger arteries.

11. ● Complications of atherosclerosis—namely,
decreased blood flow, thrombosis, or embolism
—can begin to occur in persons in their 30s.
● Women are protected until after menopause.
● Atherosclerotic plaques can cause harm in
several ways. The lumen of the blood vessel
may become significantly narrowed, or
occluded, by the plaque.
●

15. Risk factors

16. Hypertension
● The upper limit of normal blood pressure is 80 mm Hg
diastolic and 120 mm Hg systolic.
● Systolic blood pressure is reflective of the force of the heart’s
contraction as it expels blood into the aorta.
● Systolic hypertension also may be produced by increased
cardiac output, such as occurs with exercise, hyperthyroidism,
or fever.
● Diastolic pressure represents the minimum pressure within
arteries between heart contractions and is reflective of muscle
tone in small arteries, or systemic (or total) peripheral
resistance.

17. ● Mean arterial pressure, which very roughly can
be thought of as the average of the systolic and
diastolic pressures, is the product of cardiac
output and systemic peripheral resistance.
●

19. Causes of Hypertension

24. Vasculitis
● Characterized by accumulations of acute and/or
chronic inflammatory cells in the walls of and
scattered around vessels.
● Pain and symptoms related to ischemia or
infarction of the tissue supplied by the involved
artery.
●

25. Systemic lupus erythematosus
(SLE)
● Systemic lupus erythematosus (SLE), an autoimmune
disease.
● Sx: “butterfly rash” over the bridge of the nose to renal
disease, pleuritic chest pain, arthritis, muscle pain, fevers,
hematologic abnormalities, or mental conditions such as
psychosis or convulsions.
● Necrotizing (destructive) vasculitis appears to underlie many
of the symptoms and can be seen in virtually any tissue.
● Serum antibodies to cell nuclei are detected by the
antinuclear antibody test (ANA), which is a sensitive test for
this disorder.

26. ● Polyarteritis nodosa is another type of
vasculitis.
● Nodular inflammatory thickening of medium-
sized arteries, particularly those of the kidneys,
intestines, and skeletal muscles.
● Inflammation of these arteries may lead to
luminal occlusion, resulting in small to medium-
sized infarcts in many organs.