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Physiology

Bronchitis = Irreversible Bronchioconstriction
 .    Causes - Infection, Air polution, cigarette smoke

a.    Primary Defect = Enlargement & Over Activity of Mucous Glands, Secretions very viscous
b.    Hypertrophy & hyperplasia, Narrows & Blocks bronchi, Lumen of airway, significantly narrow
c.    Impaired Clearance by mucocillary elevator
d.    Microorganism retension in lower airways,Prone to Infectious Bronchitis, Pneumonia
e.    Permanent Inflamatory Changes IN epithelium, Narrows walls, Symptoms, Excessive sputum, coughing
f.    CAN CAUSE EMPHYSEMA

Proteinuria—Protein content in urine, often due to leaky or damaged glomeruli.

Oliguria—An abnormally small amount of urine, often due to shock or kidney damage.

Polyuria—An abnormally large amount of urine, often caused by diabetes.

Dysuria—Painful or uncomfortable urination, often from urinary tract infections.

Hematuria—Red blood cells in urine, from infection or injury.

Glycosuria—Glucose in urine, due to excess plasma glucose in diabetes, beyond the amount able to be reabsorbed in the proximal convoluted tubule.

Cells, cytoplasm, and organelles:

  • Cytoplasm consists of a gelatinous solution and contains microtubules (which serve as a cell's cytoskeleton) and organelles
  • Cells also contain a nucleus within which is found DNA (deoxyribonucleic acid) in the form of chromosomes plus nucleoli (within which ribosomes are formed)
  • Organelles include:
  1. Endoplasmic reticulum : 2 forms: smooth and rough; the surface of rough ER is coated with ribosomes; the surface of smooth ER is not , Functions include: mechanical support, synthesis (especially proteins by rough ER), and transport
  2. Golgi complex consists of a series of flattened sacs (or cisternae) functions include: synthesis (of substances likes phospholipids), packaging of materials for transport (in vesicles), and production of lysosomes
  3. Lysosome : membrane-enclosed spheres that contain powerful digestive enzymes , functions include destruction of damaged cells & digestion of phagocytosed materials
  4.  Mitochondria : have double-membrane: outer membrane & highly convoluted inner membrane
    1. inner membrane has folds or shelf-like structures called cristae that contain elementary particles; these particles contain enzymes important in ATP production
    2. primary function is production of adenosine triphosphate (ATP)
  5. Ribosome-:composed of rRNA (ribosomal RNA) & protein , primary function is to produce proteins
  6. Centrioles :paired cylindrical structures located near the nucleas , play an important role in cell division
  7. Flagella & cilia - hair-like projections from some human cells
    1. cilia are relatively short & numerous (e.g., those lining trachea)
    2. a flagellum is relatively long and there's typically just one (e.g., sperm)
    • Villi  Projections of cell membrane that serve to increase surface area of a cell (which is important, for example, for cells that line the intestine)

Each hormone in the body is unique.  Each one is different in it's chemical composition, structure, and action.  With respect to their chemical structure, hormones may be classified into three groups: amines, proteins, and steroids.

 

 Amines- these simple hormones are  structural variation of the amino acid tyrosine.  This group includes thyroxine from the thyroid gland and epinephrine and norepinephrine from the adrenal medulla.

Proteins- these hormones are chains of amino acids.  Insulin from the pancreas, growth hormone from the anterior pituitary gland, and calcitonin from the thyroid gland are all proteins.  Short chains of amino acids are called peptides.  Antidiuretic hormone and oxytocin, synthesized by the hypothalamus, are peptide hormones.

Steroids- cholesterol is the precursor for the steroid hormones, which include cortisol and aldosterone from the adrenal cortex, estrogen and progesterone from the ovaries, and testosterone from the testes.

Hypoxia

  • Hypoxia is tissue oxygen deficiency
  • Brain is the most sensitive tissue to hypoxia: complete lack of oxygen can cause unconsciousness in 15 sec and irreversible damage within 2 min.
  • Oxygen delivery and use can be interrupted at several sites

 

Type of
Hypoxia

O2 Uptake
in Lungs

Hemoglobin

Circulation

 Tissue O2 Utilization

 Hypoxic

 Low

Normal

Normal

Normal

 Anemic

 Normal

 Low

Normal

Normal

 Ischemic

 Normal

Normal

 Low

Normal

 Histotoxic

 Normal

Normal

Normal

 Low

  • Causes:
    • Hypoxic: high altitude, pulmonary edema, hypoventilation, emphysema, collapsed lung
    • Anemic: iron deficiency, hemoglobin mutations, carbon monoxide poisoning
    • Ischemic: shock, heart failure, embolism
    • Histotoxic: cyanide poisoning (inhibits mitochondria)

 

  • Carbon monoxide (CO) poisoning:
    • CO binds to the same heme Fe atoms that O2 binds to
    • CO displaces oxygen from hemoglobin because it has a 200X greater affinity for hemoglobin.
    • Treatment for CO poisoning: move victim to fresh air. Breathing pure O2 can give faster removal of CO

 

  • Cyanide poisoning:
    • Cyanide inhibits the cytochrome oxidase enzyme of mitochondria
    • Two step treatment for cyanide poisoning:
      • 1) Give nitrites
        • Nitrites convert some hemoglobin to methemoglobin. Methemoglobin pulls cyanide away from mitochondria.
      • 2) Give thiosulfate.
        • Thiosulfate converts the cyanide to less poisonous thiocyanate.

The Adrenal Glands

The adrenal glands are two small structures situated one at top each kidney. Both in anatomy and in function, they consist of two distinct regions:

  • an outer layer, the adrenal cortex, which surrounds
  • the adrenal medulla.

The Adrenal Cortex

cells of the adrenal cortex secrete a variety of steroid hormones.

  • glucocorticoids (e.g., cortisol)
  • mineralocorticoids (e.g., aldosterone)
  • androgens (e.g., testosterone)
  • Production of all three classes is triggered by the secretion of ACTH from the anterior lobe of the pituitary.

Glucocorticoids

They Effect by raising the level of blood sugar (glucose). One way they do this is by stimulating gluconeogenesis in the liver: the conversion of fat and protein into intermediate metabolites that are ultimately converted into glucose.

The most abundant glucocorticoid is cortisol (also called hydrocortisone).

Cortisol and the other glucocorticoids also have a potent anti-inflammatory effect on the body. They depress the immune response, especially cell-mediated immune responses. 

Mineralocorticoids

The most important of them is the steroid aldosterone. Aldosterone acts on the kidney promoting the reabsorption of sodium ions (Na+) into the blood. Water follows the salt and this helps maintain normal blood pressure.

Aldosterone also

  • acts on sweat glands to reduce the loss of sodium in perspiration;
  • acts on taste cells to increase the sensitivity of the taste buds to sources of sodium.

The secretion of aldosterone is stimulated by:

  • a drop in the level of sodium ions in the blood;
  • a rise in the level of potassium ions in the blood;
  • angiotensin II
  • ACTH (as is that of cortisol)

Androgens

The adrenal cortex secretes precursors to androgens such as testosterone.

Excessive production of adrenal androgens can cause premature puberty in young boys.

In females, the adrenal cortex is a major source of androgens. Their hypersecretion may produce a masculine pattern of body hair and cessation of menstruation.

Addison's Disease: Hyposecretion of the adrenal cortices

Addison's disease has many causes, such as

  • destruction of the adrenal glands by infection;
  • their destruction by an autoimmune attack;
  • an inherited mutation in the ACTH receptor on adrenal cells.

Cushing's Syndrome: Excessive levels of glucocorticoids

In Cushing's syndrome, the level of adrenal hormones, especially of the glucocorticoids, is too high.It can be caused by:

  • excessive production of ACTH by the anterior lobe of the pituitary;
  • excessive production of adrenal hormones themselves (e.g., because of a tumor), or (quite commonly)
  • as a result of glucocorticoid therapy for some other disorder such as
    • rheumatoid arthritis or
    • preventing the rejection of an organ transplant.

The Adrenal Medulla

The adrenal medulla consists of masses of neurons that are part of the sympathetic branch of the autonomic nervous system. Instead of releasing their neurotransmitters at a synapse, these neurons release them into the blood. Thus, although part of the nervous system, the adrenal medulla functions as an endocrine gland.The adrenal medulla releases:

  • adrenaline (also called epinephrine) and
  • noradrenaline (also called norepinephrine)

Both are derived from the amino acid tyrosine.

Release of adrenaline and noradrenaline is triggered by nervous stimulation in response to physical or mental stress. The hormones bind to adrenergic receptors  transmembrane proteins in the plasma membrane of many cell types.

Some of the effects are:

  • increase in the rate and strength of the heartbeat resulting in increased blood pressure;
  • blood shunted from the skin and viscera to the skeletal muscles, coronary arteries, liver, and brain;
  • rise in blood sugar;
  • increased metabolic rate;
  • bronchi dilate;
  • pupils dilate;
  • hair stands on end (gooseflesh in humans);
  • clotting time of the blood is reduced;
  • increased ACTH secretion from the anterior lobe of the pituitary.

All of these effects prepare the body to take immediate and vigorous action.

Bile contains:

  • bile acids. These amphiphilic steroids emulsify ingested fat. The hydrophobic portion of the steroid dissolves in the fat while the negatively-charged side chain interacts with water molecules. The mutual repulsion of these negatively-charged droplets keeps them from coalescing. Thus large globules of fat (liquid at body temperature) are emulsified into tiny droplets (about 1 µm in diameter) that can be more easily digested and absorbed.

 

  • bile pigments. These are the products of the breakdown of hemoglobin removed by the liver from old red blood cells. The brownish color of the bile pigments imparts the characteristic brown color of the feces.

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