The basic anatomy and Physiology of Autonomic nervous system (Sympathetic and parasympathetic nervous system)

ANATOMY

• Sympathetic Division
• leave CNS at thoracic or lumbar levels (“thoracolumbar system”)
• preganglionic neurons are SHORT. Postganglionic neurons are long, traveling rest of the way to body organs, glands, & vessels.
• almost all release NE as their transmitter (except those to sweat glands)

• Parasympathetic Division
• leave CNS from the brain or from sacral cord (“craniosacral”).
• preganglionic neurons are LONG and go all the way out to body organs to reach ganglia.
• postganglionic neurons are short, going from those ganglia to nearby organ/gland cells.
• All release ACh.
• Parasympathetic nerves tend to operate individually, as needed.
• Parasympathetic ganglia are near to organs.

FUNCTIONS

 A. SYMPATHETIC DIVISION (Thoracolumber):

 Also called fight, fright and flight response

 

• Easy to remember and understand that when you are nervous, you sweat; when afraid, hair stand; when excited blood pressure rises (vasoconstriction):  these are sympathetic processes.
• Also causes: dry mouth, pupils to dilate, increased heart & respiratory rates to increase O2 to skeletal muscles, and liver to release glucose.

•          ･Acceleration of heart and lung action･Inhibition of stomach and intestinal action

•          ･Constriction of blood vessels in many parts of the body

•          ･Dilation of blood vessels for muscles

•          ･Inhibition of tear glands and salivation

•          ･Dilation of pupil

•          ･Relaxation of bladder

•          ･Inhibition of erection

B. PARASYMPATHETIC DIVISION (Craniosacral):

Also called Rest and digest response

• Cranial outflow
• III ( Oculomotor) - pupils constrict
• VII (Facial)  - increasing tears, nasal mucus, saliva
• IX (Glossopharyngeal) – parotid salivary gland
• X (Vagus) – visceral organs of thorax & abdomen:
• Stimulates digestive glands
• Increases motility of smooth muscle of digestive tract
• Decreases heart rate
• Causes bronchial constriction
• Sacral outflow (S2-4):
• Supply 2^nd half of large intestine (stimulation of intestinal secretion)
• Supply all the pelvic (genitourinary) organs:

e.g. erection ( due to vasodilatation), contraction of bladder.

Summary of the Major Types of Autonomic Receptors & Drugs:

Branch	Type	Location	Typical Agonist Drugs	Typical Antagonist Drugs
Sympathetic (adrenergic)	Alpha 1	Most vascular arterioles, Eye Sphincters of bladder & GI tract	Norepinephrine Epinephrine	Phenoxybenzamine Phentolamine Prazosin
	Alpha 2	GI tract, presynaptic sympathetic neurons, pancreas	Clonidine Epinephrine	Yohimbine
	Beta 1	Heart muscle Salivary glands Fat cells	Norepinephrine Isoproteronol Dobutamine Epinephrine	"Beta blockers" Propranolol Metoprolol
	Beta 2	Bronchioles of lung Arterioles of skeletal muscles, brain and lungs Bladder wall GI tract	Epinephrine Isoproteronol Albuterol	"Beta blockers" Propranolol Butoxamine
Parasympathetic (cholinergic)	Muscarinic (M)	Heart muscle Sphincters of bladder & GI tract Bronchioles of lung Sweat glands Iris constrictor	Acetylcholine Muscarine Carbachol	Atropine Scopolamine
	Nicotinic (N)	Neuromuscular junctions Autonomic ganglia	Acetylcholine Nicotine Carbachol	Curare

SUMMARY OF SPINAL NERVES

Spinal Nerve(s)	Innervated Body Part(s)	Symptom(s) of injury
C1	Head and Neck	Quadriplegia i.e. paralysis of both arms and both legs
C2-C4	Diaphragm	Breathing problem
C5	Deltoids, biceps	losing control on wrist or hand
C6	Wrist extenders	losing hand function
C7-T1	Triceps, hand	dexterity problems with hand and fingers
T2-T8	Chest muscles	Paraplegia i,e. paralysis of lower extremeties. Poor trunk control
T9-T12	Abdominal muscles	Paraplegia
Lumbar and Sacral	Leg muscles, bowel, bladder, sexual organs	Decreasing control of hip flexors and legs, dysfunction of bowel, bladder, and sex

SUMMARY OF CRANIAL NERVES

SUMMARY OF CRANIAL NERVES

Cranial Nerve	CN#	Brain Region	Major Functions
Olfactory	I	Cerebral Cortex	Smell
Optic	II	Limbic System	Vision
Oculomotor	III	Midbrain	Eyelid & eyeball movement; pupil dilation
Trochlear	IV	Pons	Control downward & lateral eye movement
Trigeminal	V	"	Chewing; sensation of face & mouth
Abducens	VI	"	Control lateral eye movement
Facial	VII	"	Control most facial expressions; secretion of tears & saliva; taste;
Auditory/ Vestibulochochlear	VIII	Medulla	Hearing; balance
Glossopharyngeal	IX	"	Taste; swallowing; sensation from tongue, tonsil, pharynx, carotid blood pressure
Vagus	X	"	Sensory, motor and autonomic functions of viscera - glands, digestion, heart rate, breathing rate, aortic blood pressure
Spinal Accessory	XI	"	Controls muscles used in head movement
Hypoglossal	XII	"	Controls tongue movements

PATHOLOGY PRACTICAL # 8 Total Leukocyte Count (TLC) and its interpretation

Total Leukocyte Count (TLC) and its interpretation:

Leukocytes include neutrophils, eosinophils, and basophils, monocytes and lymphocytes.

Granulocytes only include neutrophils, eosinophils, and basophils. While other cells are called agranulocytes such as lymphocytes, monocytes etc.. Neutrophils are the most efficient at phagocytosis and are the principal cells of innate immune defense against bacteria and fungi. 

TLC is recommended to evaluate White cell counting for diagnosing bacterial and viral infections, toxic metabolic processes, diagnosing leukemia stages etc.

                     Normal Adult Total 3500-10,000 cells/cc

CELL TYPE	RANGE (AVG)
Neutrophil	2000-7000 (3700)
Lymphocytes	1500-4000 (2500)
Monocytes	200-1000 (400)
Eosinophils	0-700 (150)
Basophils	0-150 (30)

CLINICAL UTILITY OF CELL COUNTS

CLINICAL CONDITION	DIFFERENTIAL COUNT FINDING
acute infection	granulocytosis
chronic inflammation	monocytosis
parasitic infection	eosinophilia
viral infection	lymphocytosis
aplastic anemia	neutropenia
acute leukemia	immature cells or blasts

Marked Leukocytosis can be due to benign or malignant causes:

Peripheral Blood Findings	(non-malignant)	Chronic Myelogenous Leukemia
WBC > 100000	rare	often
Basophilia	rare	often
Chromosomal abnormalities	never	always
Splenomegaly	rare	often

 



Eosinophils

Special function of eosinophils is to fight helminths, ticks, and parasites.

Eosinophils can also suppress or enhance hypersensitivity by mobilizing or destroying histamine.

Eosinophils have many red granules.

Eosinophilia is almost always caused by allergic reactions or parasitic infections.  It can cause       tissue destruction.

Basophils

Basophils release histamine and heparin.

They are full of large purple granules.

Basophilia is associated with acute allergic reactions like food allergies.

Monocytes

Monocytes are important for phagocytosis They are also involved in clearing apoptotic cells.

Monocytosis is caused by chronic infection or an inflammatory disease.

Lymphocytes

There are several kinds of lymphocytes (although they all look alike under the microscope), each with different functions to perform . The most common types of lymphocytes are

• B lymphocytes ("B cells"). These are responsible for making antibodies.
• T lymphocytes ("T cells"). There are several subsets of these:
  • inflammatory T cells that recruit macrophages and neutrophils to the site of infection or other tissue damage
  • cytotoxic T lymphocytes (CTLs) that kill virus-infected and, perhaps, tumor cells
  • helper T cells that enhance the production of antibodies by activating B cells

Although bone marrow is the ultimate source of lymphocytes, the lymphocytes that will become T cells migrate from the bone marrow to the thymus. where they mature. Both B cells and T cells also take up residence in lymph nodes, the spleen and other tissues where they

• encounter antigens;
• continue to divide by mitosis;
• mature into fully functional cells.

Common Causes of Altered Leukocyte Counts
	Decreased	Increased
Neutrophil	Congenital Hereditary neutropenia Acquired Bone marrow disease Immune reactions Drugs Gram-negative septicemia	Acquired Infections Tissue destruction Corticosteroids, lithium Neoplastic growth Leukemoid reaction, pregnancy, smoking
Lymphocyte	Congenital Congenital immunodeficiency disease Acquired Severe infection Drugs (Corticosteroids, alkylating) GI disease Immunodeficiency	Acquired Viral infection (EBV, hepatitis, etc.) Some fungal, parasitic infections Rare bacterial infection (Pertussis) Allergic reactions/drug sensitivities, smoking, CLL Immunologic disease
Monocyte	Acquired Hairy cell leukemia Corticosteroids	Acquired Mycobacterial infection Tuberculosis, syphilis Subacute bacterial endocarditis Inflammatory responses Myeloproliferative disorders
Eosinophil	Acquired Bacterial infection ACTH administration	Acquired Parasitic infections, Asthma, Hypersensitivity reactions Pulmonary disease Myeloproliferative diseases
Basophil	Acquired Corticosteroids	Acquired Myeloproliferative syndromes Lymphoproliferative disease Hypersensitivity reactions Hodgkin’s disease Some viral infections Myxedema