KIDNEYS (RENALS) FAILURE-1 INTRODUCTORY

A SHORT INTRODUCTION TO KIDNEYS(RENTALS) -1

Fig-1

Kidneys are two bean-shaped excretory organs located against the back muscles in the upper abdominal area. They sit opposite each other at the right and left sides of the spine. The right kidney is fitted a little lower than the left kidney to accommodate the liver. See Fig-1 above.

Blood Supply To Kidneys(The Renal Circulation):-

Fig 2

Despite their smaller sizes the kidneys receive almost 20% of the total cardiac output. They are well supplied with renal arteries which branch from the aorta at the abdominal region. Kidneys after receiving about 20 to 25% of the cardiac output it filters and cleans the blood from many harmful wastes and impurities such as urea, creatinine, hippurates, uric acid, and many metabolic medical wastes. Also kidneys excrete excess minerals to keep the balance of the electrolytes in the body. After cleaning the blood they consume 3% of the blood for their own oxygen need. The remaining cleaned and deoxygenated blood is drained into the veins and return back to the heart. (See Fig.2 above).

THE NEPHRONS AND THE URINE FORMATION:-

Fig-3 A

Fig 3B

The two figures are shown above (3A and 3B)are for illustrative purposes only. The nephrons are the fundamental units of the kidneys. There are about one million nephrons in each kidney.
These number of nephrons are really the Grace and Gift of the Almighty to the human lives. In our everyday life, we are abusing our kidneys. By our unhealthy eating and drinking habits, stress situations, the dirty atmosphere we are killing the nephrons smoothly. To combat these abuses God has given us this huge number of nephrons with a Great Kindness. All praises to the Almighty God.
As shown in the figures above a nephron is composed of the following parts.
1.The Bowman's Capsule:
The cup-shaped head like part. This is the first part of the nephron. It is like a sac enclosing the glomerulus. The sac is 8 to 10 nm. The blood that enters into this portion is already ultra-filtered by leaving back the macrocells and proteins. The filtrate contains 0.05 % of proteins.
2.Glomerulus:-
A small ball-shaped knitted form of tiny capillaries fitted inside the Bowman's capsule. Blood is filtered in this portion of the nephron.
3.Proximal Convoluted Tubule:-
Pre or Proximal Convoluted Tubule (PCT) is the coiled tubule immediately following down the Bowman's Capsule. In this part when the filtrate passes, important nutrients like glucose, and proteins in the form of peptides are reabsorbed back into the blood. Water is absorbed along with sodium and bicarbonate ions in this part. Further in this region urea, chloride, potassium, lactate, phosphate, and bicarbonate are also absorbed back into the blood.
4.Loop Of Henley (Descending):-
This is the narrowed descending portion of the PCT.
After some water is absorbed along with various ions mentioned above in the PCT a one-third of the filtrate which is hypotonic reaches in this portion. Here the tubule is highly permeable to water only and not the solute. Water is reabsorbed back to the blood by leaving a highly concentrated filtrate to pass down into the bottom of the loop. Afterward the hypertonic filtrate passes upwards to the ascending loop of Henley.
5.Loop of Henley (Ascending):-
In this portion the loop cells are permeable only o the solutes and not to the water. Thus solutes like sodium, potassium, and chloride ions are reabsorbed back to the blood, with the exchange of hydrogen out into the filtrate. Hence the filtrate is more and more diluted to hypotonic with water.
In general the movement of the luminal fluid in the loop region is sufficiently slow in order to maintain the concentration of the urine to keep the osmolarity balance in the medulla. Sodium, potassium, calcium, chloride, and bicarbonate ions are reabsorbed in the ascending loop of Henley.
6.Distal Convoluted Tubule (DCT):-

This portion of the nephron is located again back upward to the cortex region near the end part of the nephron. After passing through the ascending loop the filtrate enters into the lumen of the DCT. Here minerals like calcium, sodium, and chloride are reabsorbed with the exchange of potassium by the action of vasopressin (Anti Diuretic Hormone)  secreted from the posterior pituitary. The hydrogen ion is also secreted into the filtrate in order to maintain the pH of the urine around 5(acidic).
7. Collecting Tubules And Collecting Ducts:-
Collecting tubule is the nonvascularized portion of the DCT which drains the urine into the collecting duct. All the collecting ducts from all the nephrons are combined to form a single ureter which descends down and open at the upper mouth of the bladder.

Ureter:-

Ureters are two single tubes from each kidney receives urine from the collecting ducts and carries urine down to the urinary bladder.

THE LOCATION OF THE NEPHRON

Fig 4 A

Fig 4 B

The location of the nephrons are simplified diagrammatically in the above two figures (Fig 4A and 4B)

A single nephron has been represented for a simple understanding of their locations inside the kidney. A rough cross-section of the kidney has been figured above. In the cross-section (4B) the nephron except for its loop part the remaining parts like Bowman's capsule, the coiled tubules are all situated at the peripheral cortex of the kidney. Only the loop of Henley and the collecting ducts are situated in the medullary region.
In the cross-section (Fig 4A) it has been shown that the cortex is more vascularised than the medulla. Only the loop portion is vascularised in the medulla. The collecting tubule and the collecting duct are exempted from vascularization as there are no cleansing activities there.
one-third of the medullary region is occupied by the pelvis. All collecting ducts from various nephrons are grouped into the pelvis. All pelvises are unified to form the single ureter. This is the simplified physiology and anatomy of the kidney.                           Continued......

THYROID UNDER ACTIVITY EFFECTS IN ECG

ECG EFFECTS OF HYPOTHYROIDISM

HYPOTHYROIDISM EFFECTS

https://www.linkedin.com/pulse/thyroid-under-activity-ecg-seyed-ali/?trackingId=8sJR43x6QnKqcMkADkNKWg%3D%3D
Hypothyroidism is the condition in which the thyroid gland is unable to secrete sufficient quantity of its hormone thyroxine (T4). This disease is due to various causes such as 1.thyroid inflammation or thyroid cell necrosis due to a disease called Hashimoto Autoimmunity Disease.
This is one of the very common and very important causes of thyroid dysfunction.
Our body is equipped by nature with self-protection forces against invading pathogenic cells such as bacteria. When an invading pathogen enters into our body, our immune apparatus immediately responds to it by sending fighting cells to the area of invasion to kill the pathogen.
But due to some unexplained situation the fighting cells confused with healthy cells such as cells of the thyroid gland and kill them. This is known as Autoimmune Disease, or Hashimoto's Disease.
2.Medications for Hyperthyroidism such as Propylthiouracil, and Methimazole(Tapazole), Potassium or Sodium Iodide, and Radio Iodine (I131) if overdosed may cause thyroid gland damage.
3.Insufficient secretion of TSH from the pituitary due to some unknown pituitary disease
4.Thyroidectomy-Removal of the gland
4.Insufficient iodine intake.
To go further is beyond the scope of this ECG article. Hence to study further regarding causes, symptoms, and treatment please click here.

Hypothyroidism in ECG

In the above figure the effects of Hypothyroidism are apparent in examining the ECG.
In the lead-II recording, one can observe the elongated R-R interval which represents the presence of bradycardia (slower heart rate)
The absence of P-wave and the elongated P-R segment indicates the dysfunction of the atria.
Depression of ST-segment and the deformation of T-wave indicates the dysfunctions of the ventricles and the presence of angina.
Conclusively untreated long term hypothyroidism can precipitate many serious cardiac issues.

ECG CHANGES IN THYROID OVERACTIVITY

ECG CHANGES DURING HYPERTHYROIDISM

Fig-1

Hyperthyroidism is a serious condition in which the thyroid gland becomes overactive and produces many complications.

The thyroid is a tiny butterfly-shaped gland that is located in front of the neck just below Adam's apple.

It is producing the hormone thyroxine (T4) and triiodothyronine T3 releasing them in circulation.T3 (Triiodothyronine) which is more active than T4 (tetraiodothyronine) is highly unstable and is soon converted into T4. For details click here.

Due to the following causes hyperthyroidism may occur.

1.Excessive intake of thyroid tablets
2.Excessive secretion of TSH (Thyroid     Stimulating Hormone)
3.Grave's Disease.An autoimmune disease in which the thyroid gland produces more hormone.
4.Inflammations of the thyroid gland (Thyroiditis)
5.High iodine intake
6.Functioning adenoma
7.Severe Multinodular Goiter(SMNG)
Normally the body uses thyroid hormone to speed up metabolism, which raises and maintains the body temperature within limits.
But if the thyroid secretes high levels of the hormone then the temperature raises more rapidly with dangerous levels of anabolism and catabolism which raises energy level beyond the control. Blood pressure raises, with increased heart rate and many more complications.
Symptoms:-
1.Tremor, exciting, nervousness.
2.Anxiety
3.Tiredness, and weakness
4.Mood swings
5.High temperatures(Hyperthermia)
6.Sudden unexpected weight loss
7.Goiter(Swollen neck)
6.Increased heartbeats (Tachyarrhythmia), palpitations.
7.Rapid bowel movements
8.Sleeplessness
9.Thinning and brittle skin and hair.
10.Disturbed menstrual cycles.
Thyroid Storm:-
If hyperthyroidism is not properly cared for and treated in time it will lead to this acute condition in which all symptoms mentioned above will rise to a life-threatening dangerous level with fatal results. 
ECG EFFECTS;-

Fig-2A

In the above Fig-2A a model ECG taken during Hyperthyroidism has been present for reference.

Observe the waves P, Q, R, S, and T.The normal rhythm is highly disturbed as we have seen in past articles. To get a detailed description of a normal sinus rhythm please click here.

Fig-2B

In the above Fig-2A and Fig 2B note the records by Leads-II, III, I aVL, and aVF which give the picture of rapid heartbeats(tachyarrhythmias) by the narrowed QRS complex and the shortened R-R intervals.
Short P-R intervals indicate the rapid contractions of the atria followed by the immediate ventricular responses.
The depression of S-wave followed by elevation of the ST segment indicates the strain on the ventricles. These changes are predicting a heart attack to follow ventricular fibrillation.
Conclusively thyroid overactivity and thyroid storm should be treated in time to avoid fatal consequences.
                               (Next: Thyroid Under Activity)

EFFECTS OF MEDICINES IN ECG-BETA BLOCKERS AND CALCIUM CHANNEL BLOCKERS.-3

1.ATENOLOL(TENORMIN), PROPRANOLOL(INDERAL) AND CALCIUM CHANNEL BLOCKERS(CCB)

Atenolol is a B.P medicine commonly available in the pharmacy under the brand name as Tenormin.

It is technically known under the group as a Beta Receptor Blocker or simply as Beta Blocker.

Briefly we can say that beta-blockers are drugs that lower the blood pressure by lowering the heart rate by blocking beta-1 receptors of the adrenergic nervous system which is more concentrated on the cardiovascular network. The result also included dilation of the blood vessels and reduction of the heart rate.
This drug has notable effects on the ECG if overdosed.

Fig-1

A normal heart rhythm has been shown diagrammatically in Fig-1 above. In that, the waves P, Q, R, S, and T are clear and distinguishable.
Atenolol is a safe B.P medicine with a wider therapeutic index. It is highly water-soluble and is eliminated in the urine. It is less fat-soluble and hence it is less likely to pass into the blood-brain barrier to produce CNS effects.
But as with any other medicine if overdosed or misused by otherwise a normal person atenolol propranolol and any other beta-blocker will reduce heart rate, blood pressure followed by fatal CHF. This can be noticed in the ECG by prolonged PR segment, wider QRS complex, and elevated or depressed ST segment.

Fig-2

In Fig 2 above a model, ECG has been shown with the effects of all beta-blockers such as atenolol, propranolol(Inderal), metoprolol(Lopressor)and calcium channel blockers such as diltiazem(Dilzem, Cartia), verapamil(Isoptin), amlodipine(Norvasc) and nifedipine(Procardia).

In the above ECG examine the lead-II the master lead record which shows the depressed ST segment, with a more depressed S-wave, and the absence of Q-wave.

The aVL record shows (marked by a small red squire) the absence of P, and T-wave and elongated P-R and S-T segments or intervals.

This indicates severe bradycardia (reduced heartbeat)

extremely low pressure and congestive heart failure (CHF)

                                                                                                   
                                                                                                         Fig 3A

Fig 3B

In the above two diagrams (Fig 3A and 3B) the effects of verapamil (Isoptin) a CCB drug on ECG taken in an old man who has been overdosed by the drug.

In Fig 3A a simulated image has been explained.

Note down the marked deviation of Phase-0 more towards the right. This is because calcium channels are blocked and the entry of calcium is restricted with the result of the shortening of the plateau Phase-2.

The deviation has been explained in the down by elongated PR-interval widening of the QRS complex and the elongated ST-segment.

These changes can be easily noted in Fig-3B in the Lead-II records. The elongated intervals and segments and the QRS widening are marked by a blue rectangle.
Conclusively the ECG effects of both beta-blockers and CCBs are similar by many factors such as elongated PR-intervals, widened QRS-complex, elongated ST-segment, etc which indicates sinus bradycardia followed by CHF.
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