Physiology

Argyll Robertson Pupil (ARP):
Hallmark of neurosyphilis
1. Light-near dissociation (no reaction to light but brisk response to near).
2. Both pupils usually involved, but the degree may be asymmetrical.
3. Pupils are small and frequently irregular in shape.
4. Pupils dilate poorly after instillation of mydriatics.
5. To make a diagnosis of ARP vision in the affected eye must be normal.

Gastrin’s principal physiologic action is to increase H+ secretion. H+ secretion decreases the pH of the stomach contents. The decreased pH, in turn, inhibits further secretion of gastrin—a classic example of negative feedback.

Primary (ACTH) Addison's disease Common causes
·       Autoimmune
o   Sporadic
o   Polyglandular syndromes
·       Tuberculosis
·       HIV/AIDS
·       Metastatic carcinoma
·       Bilateral adrenalectomy
Rare causes
·       Lymphoma
·        Intra-adrenal hemorrhage (Waterhouse-Friedrichsen syndrome following meningococcal sepsis)
·       Amyloidosis
·       Haemochromatosis

Explanation : Stretch reflex is a monosynaptic reflex,Golgi tendon reflex/Clasp-knife reflex is disynaptic reflex,flexor withdrawl reflex is a polysynaptic reflex.
Ref : BRS Physiology 7th edition (Table- 2.8)

Explanation :

Ref : Sembulingam 6th edition (Figure-139.2)

Reference: Guyton 14th; P- 492

GH, Glucagon, cortisol etc. are diabetogenic hormones.

Primary sex organ in male is testes, whereas ovary in female.

Explanations:
Agglutinogens are present on RBC membrane & agglutinins are present on serum.

[Ganong 24th p-48]

Explanation:
The RR interval is the time between successive QRS complexes and is usually used to measure the cardiac cycle length (i.e. duration of ventricular cardiac cycle). RR interval is an indicator of ventricular rate.

Thyroid hormone increase gut motility. So hypothyroid state causes constipation.

Explanations:
There are three superfamilies of molecular motor proteins in the cell that use the energy of ATP to generate force, movement, or both. Myosin is the force generator for muscle cell contraction. Cellular myosins can also interact with the cytoskeleton (primarily thin filaments) to participate in contraction as well as movement of cell contents. Kinesins and cellular dyneins are motor proteins that primarily interact with microtubules to move cargo around the cells.

Semen
The fluid that is ejaculated at the time of orgasm, the semen, contains sperm and the secretions of the seminal vesicles, prostate, Cowper glands, and, probably, the urethral glands. An average volume per ejaculate is 2.5-3.5 mL after several days of abstinence from sexual activity. The volume of semen and the sperm count decrease rapidly with repeated ejaculation.
Even though it takes only one sperm to fertilize the ovum, each milliliter of semen normally contains about 100 million sperm. Reduction in sperm production is associated with infertility: 50% of men with counts of 20-40 million/mL and essentially all of those with counts under 20 million/mL are sterile. The presence of many morphologically abnormal or immotile spermatozoa also correlates with infertility.
The prostaglandins in semen, which come from the seminal vesicles, are at high concentrations, but their function in semen is unknown. The causes of male infertility, as well as the underlying mechanisms of sperm in fertilization, are used as clues in developing male contraception .

Explanation : Lateral nucleus of hypothalamus acts as feeding centre & Ventromedial nucleus of hypothalamus acts as satiety centre.
Ref : Sembulingam 6th edition (Table- 149.2)

Explanation : Diencephalon includes thalamus, hypothalamus, subthalamus, metathalamus.
Ref : Sembulingam 6th edition (Page- 758)

PCT has maximum capacity of reabsorption. Most of the reabsorption takes place here.

HCl activates pepsinogen to active pepsin.

Medial geniculate body involve in hearing.

Va/Q is infinity : No perfusion but ventilation remains normal.
Causes:
1. Embolism
2. Emphysema
3.Bronchiectasis

60% of TBW is fluid where 40% is ICF & 20 is ECF

Composition of normal human pancreatic juice.
Cations: Na+, K+, Ca2+, Mg2+ (pH approximately 8.0)
Anions: HCO3-, Cl-, SO42-, HPO42-
Digestive enzymes -95% of protein in juice)
Other proteins

The interpeduncular fossa
infront by the optic chiasma,
behind by the antero-superior surface of the pons,
antero-laterally by the converging optic tracts,
postero-laterally by the diverging cerebral peduncles.

Explanations:
Mean corpuscular haemoglobin value in range is 27-32pg & average 29pg.

Mainly due to calcium influx

▶  due to slow long lasting ca²+- Na+

▶  coincides with ventricular systole

▶  Results in prolonged refractory period

Norepinephrine has shortest half-life.

Ganong 26th Page 624
 

Myelinated Nerve Fibre:

1. The nerves that are insulated by a sheath or myelin called myelinated nere fibre.
2. These are made up of lipid & protein and so, appear white.
3. These have nodes of Ranvier which always constant in number.
4. Nerve fibres outside CNS and myelinated.

Non-Myelinated nerve fibre:
1. The nerves which lack such sheath are called non-myelinated nerve fibre.
2. They appear grey because of absence of myelin sheath.
3. They do not have node of Ranvier.
4. Post-ganglionic sympathetic nerves are non-myelinated.

Features of proximal acidification:
1. It is a high capcity system used for huge bicarbonate reabsorption mainly in PCT and partly in ALH (if HCO3- escape reabsorption in PCT).
2. Here secreted Ht from tubular cell is titrated in tubular fluid by filtered HCO3- for its reabsorption with no net loss of H+ from body and no net gain of HCO3- to blood. Merely proportional replacement of filtered HCO3- in blood occur by this mechanism.
3. Simply it helps to maintain the present bicarbonate status (alkali reserve) of body without urinary HCO3- loss. It does nothing to change the acid base status of body.
4. It does not create high luminal H+ concentration.
5. It creates a very low pH gradient by decreasing filtrate pH from 7.4 to 6.8.
6. It is important because it saves huge amount of HCO3- per day (about 4500 mmol) by preventing their urinary loss. Kidney cannot be in a position to excrete non volatile acid load without prior reabsorption of all filtered HCO3- because one HCO3- loss from the body is equivalent to one H+ gain to the body.

Membrane must be present.

Relative hypoxia ( Type 1 B Lactic Acidosis)
1.Seizure
2.Severe Exercise

ABC of Biochemistry 6th - P: 371

Explanations:
Platelet has no nucleus.

Hypoparathyroidism leads to hypocalcemia, by decreasing the resorption of calcium from bones. Hypocalcemia causes neuromuscular hyperexcitability, resulting in hypocalcemic tetany. Normally, tetany occurs when plasma calcium level falls below 6 mg/dL from its normal value of 9.4 mg/dL.

Hypokalemia occurs in Conn's syndrome

Loss of ankle jerk with extensor planter response
•       Subacute combined degeneration of spinal cord
•        Friedreich’s ataxia
•       Taboparesis
•       Multiple sclerosis
•       DM with cervical myelopathy.

Aldosterone is produced in the zona glomerulosa of the adrenal cortex because that layer contains the enzyme for conversion of corticosterone to aldosterone (aldosterone synthase). Cortisol is produced in the zona fasciculata. Androstenedione and dehydroepiandrosterone are produced in the zona reticularis. Testosterone is produced in the testes, not in the adrenal cortex.

Insulin is major anabolic hormone of the body

Explanation : NGF plays an important role in treating many nervous disorders such as Alzheimer disease, neuron degeneration in aging and neuron regeneration in spinal cord injury. Commercial preparation of Brain-derived Neurotrophic Growth Factor is used to treat motor neuron diseases.
GDNF is found in neuroglial cells. It has a potent protective action on dopaminergic neurons. It is used for the treatment of Parkinson disease.
CNTF is secreted in peripheral nerves, ocular muscles and cardiac muscle. It protects neurons of ciliary ganglion and motor neurons.
Ref : Sembulingam 6th edition (Page- 763)

Composition
FFP contains labile as well as stable components of the coagulation, fibrinolytic and complement systems, the protiens that maintain oncotic pressure and modulate immunity.
In addition fats, carbohydrates and minerals are present in concentrations similar to circulation.
The analysis of 35 samples of FFP show mean concentrations of of 535mg/dl Glucose, 172mEq/L. Na+, 73mEq/L Cl-, Cl-, 3.5mEq/Lk 3.5mEq/L. K+, 15mEq/L HCO3-and  protien with 60% albumin. 5-5g/dl
Thus FFP is a hyperosmolal, hyperglycemic, hypernatremic and hypochloremic solution.
It is a less effective volume expander than other albumin containing solutions, due to its lower albumin content.

Indications
Multiple coagulation factor deficiencies e.g.
DIC
Massive blood transfusion
Liver disease
Active or ongoing bleeding with abnormal coagulation tests
"Thrombotic thrombocytopaenic purpura
Vitamin K deficiency associated with active bleeding

Thiazide diuretics have a unique effect on the distal tubule; they increase Ca2+ reabsorption, thereby decreasing Ca2+ excretion and clearance. Because parathyroid hormone (PTH) increases Ca2+ reabsorption, the lack of PTH will cause an increase in Ca2+ clearance. Furosemide inhibits Na+ reabsorption in the thick ascending limb, and extracellular fluid (ECF) volume expansion inhibits Na+ reabsorption in the proximal tubule. At these sites, Ca2+ reabsorption is linked to Na+ reabsorption, and Ca2+ clearance would be increased. Because Mg2+ competes with Ca2+ for reabsorption in the thick ascending limb, hypermagnesemia will cause increased Ca2+ clearance.

Testes in male & ovary in female

Aquaporin-1 is localized to both the basolateral and apical membrane of the proximal tubules and its presence allows water to move rapidly out of the tubule along the osmotic gradients set up by active transport of solutes, and isotonicity is maintained. 60-70% of filtered water is reabsorbed in PCT.

The acetylcholine-gated channel has a diameter of about 0.65 nanometer, which is large enough to allow the important positive ions-sodium (Na+), potassium (K+), and calcium (Ca2+)-to move easily through the opening. Patch clamp studies have shown that one of these channels, when opened by acetylcholine, can transmit 15,000 to 30,000 sodium ions in 1 millisecond. Conversely, negative ions, such as chloride ions, do not pass through because of strong negative charges in the mouth of the channel that repel these negative ions.

Explanations:
The time required for coagulation to take place is known as the prothrombin time. The shortness of the time is determined mainly by the prothrombin concentration. The normal prothrombin time is about 12 seconds.

Explanation:
Pulses bigeminy: This is due to premature ectopic beats following every sinus beat. The pulse rhythm is not regular because every weak pulse is premature.

Effects of low ionized Ca2+
1.  Increased excitability of nerve & muscles.
2.  Increased membrane permeability
3.  Impaired blood clotting
4.  Tetany
5.  Rickets (in children)
6.  Osteomalacia (In adult)

[Ganong 24th p-524]

Explanations: Agglutinogens are present on RBC membrane & agglutinins are present on serum.

Presbycusis is age related hearing impairment.

Xerostomia means dry mouth. It is also called pasties or cottonmouth. It is due to hyposalivation or absence of salivary secretion (aptyalism).

The H+/monocarboxylate cotransporter (MCT) recognizes monocarboxylates such as lactate, pyruvate, acetoacetate, and β-hydroxybutyrate. It is a proton-driven transporter with a coupling stoichiometry of 1 H+ : 1 monocarboxylate and, thus, MCT is an electroneutral transporter (Fig. 4). The direction of transport is governed by the prevailing proton gradient.

Pain Initiators
• Glutamate - Central
• Substance P - Central
• Brandykinin - Peripheral
• Prostaglandins - Peripheral
• Aspartate
Pain Inhibitors
• Serotonin
• Endorphins
• Enkephalins
• Dynorphin
• GABA
• Glycine

With renin high and aldosterone high (secondary hyperaldosteronism)
• Inadequate renal perfusion, e.g. diuretic therapy, cardiac failure, liver failure, nephrotic syndrome, renal artery stenosis.
• Renin-secreting renal tumor (very rare)

Hypoxia (decreased level of oxygen in blood) stimulates kidney to secrete EPO.

Glycine has both excitatory and inhibitory effects in the CNS. When it binds to NMDA receptors, it makes them more sensitive to the actions of glutamate. Glycine may spill over from synaptic junctions into the interstitial fluid and in the spinal cord; for example, it may facilitate pain transmission by NMDA receptors in the dorsal horn. However, glycine mediates direct inhibition in the brainstem and spinal cord.

কোন ব্যাখ্যা যোগ হয় নি।

Definite cyanosis appears whenever the arterial blood contains more than 5 grams of deoxygenated hemoglobin in each 100 ml of blood. A person with anemia almost never becomes cyanotic. Conversely, in a person with Polycythemia vera frequently has cyanosis, even under otherwise normal conditions.

Glucose is completely reabsorbed by kidney unless any abnormality.

Thyroid hormone, an amine, acts on its target tissues by a steroid hormone mechanism, inducing the synthesis of new proteins. The action of antidiuretic hormone (ADH) on the collecting duct (V2 receptors) is mediated by cyclic adenosine monophosphate (cAMP), although the other action of ADH (vascular smooth muscle, V1 receptors) is mediated by inositol 1,4,5-triphosphate (IP3). Parathyroid hormone (PTH), β1-agonists, and glucagon all act through cAMP mechanisms of action.

• ২০২৬ সালের বর্ষপণ্য : 
- পেপার ও প্যাকেজিংকে চলতি বছরের বর্ষপণ্য ঘোষণা করে ৩০তম ঢাকা আন্তর্জাতিক বাণিজ্য মেলার (ডিআইটিএফ) উদ্বোধন করা হয়েছে।
- 'পেপার ও প্যাকেজিং প্রডাক্টকে ২০২৬ সালের বর্ষপণ্য হিসেবে ঘোষণা করেন বাণিজ্য উপদেষ্টা শেখ বশিরউদ্দীন।
- বর্ষপণ্য ঘোষণার ফলে পেপার প্যাকেজিং শিল্পে নতুন বিনিয়োগ, আধুনিক প্রযুক্তির ব্যবহার, কর্মসংস্থান বৃদ্ধি এবং রফতানি আয় উল্লেখযোগ্যভাবে বাড়বে। 

উল্লেখ্য, 
- ২০২৫ সালের 'বর্ষপণ্য' ছিলো আসবাবপত্র বা ফার্নিচার। 

তথ্যসূত্র: বনিক বার্তা ও বাসস। (Link1) (Link2)

Explanation:
Internal intercostal muscle is primary expiratory muscle

Reference: Ganong 26^th; Table-2.1

Explanation : Mesencephalon is also known as midbrain. Rhombencephalon or hindbrain is subdivided into two portions:
i. Metencephalon, formed by pons and cerebellum
ii. Myelencephalon or medulla oblongata.
Midbrain, pons and medulla oblongata are together called the brainstem.
Ref : Sembullingam 6th edition (Page- 758)

When red cells become older(120days) and fragile, they are destroyed in reticulo-endothelial system. The main destruction occurs in the capillaries of red pulp of spleen because the splenic capillaries diameter is very small. So, spleen is called ‘graveyard of RBCs’.    

Explanation : Anterior hypothalamus & mamillary body regulate sleep & wakefulness.
Ref : Sembulingam 6th edition (Table- 149.2)