স্পেশাল বিসিএস (স্বাস্থ্য) - লং কোর্স

Explanation : Three areas are present in visual cortex:
i. Primary visual area (area 17), which is concerned with the perception of visual impulses.
ii. Secondary visual area or visual association area (area 18), which is concerned with the interpretation of visual impulses.
iii. Occipital eye field (area 19), which is concerned with the movement of eyes (Chapter 152). Pretectal nucleus is concerned with light reflexes.

Ref : Sembulingam 6th edition (Page- 991)

Explanation : Pupillary reflexes are classified into three types: 1. Light reflex 2. Ciliospinal reflex 3. Accommodation reflex.
Ref : Sembulingam 6th edition (Page- 994)

Explanation : Accommodation is a reflex action. When a person looks at a near object after seeing a far object, three adjustments are made in the eyeballs:
1. Convergence of the eyeballs due to contraction of the medial recti
2. Constriction of the pupil due to the contraction of constrictor pupillae of iris
3. Increase in the anterior curvature of the lens due to contraction of the ciliary muscle.
Ref : Sembulingam 6th edition (Page- 997)

Explanation : The center for accommodation lies in frontal eye field (area 8) that is situated in the frontal lobe of cerebral cortex.
Ref : Sembulingam 6th edition (Page- 997)

Explanation : Amplitude of accommodation varies with age. Amplitude of accommodation at different age groups is: 10 years = 11.0 D, 20 years = 9.5 D, 30 years = 7.5 D, 40 years = 5.5 D, 50 years = 2.0 D, 60 years = 1.2 D, 70 years = 1.0 D.
Ref : Sembulingam 6th edition (Page- 998)

Explanation : Horner syndrome is an eye disorder caused by damage to cervical sympathetic nerve. It is also called Bernard-Horner syndrome, Claude- Bernard-Horner syndrome or oculosympathetic palsy. Symptoms of Horner syndrome appear on the affected side. The symptoms are:
1. Ptosis (drooping of upper eyelid)
2. Swelling of lower eyelid
3. Miosis (abnormal constriction of pupil)
4. Enophthalmos (sinking of eyeball into its cavity)
5. Absence of sweating on affected side of the face.

Ref : Sembulingam 6th edition (Page- 998)

Explanation : First order neurons (primary neurons) are bipolar cells in the retina. Axons from the bipolar cells synapse with dendrites of ganglionic cells. Second order neurons (secondary neurons) are the ganglionic cells in ganglionic cell layer of retina. Axons of the ganglionic cells form optic nerve. Optic nerve leaves the eye and terminates in lateral geniculate body. Third order neurons are in the lateral geniculate body. Fibers arising from here, reach the visual cortex.
Ref : Sembulingam 6th edition (Page- 989)

Explanation : Optic tract is formed by uncrossed fibers of optic nerve on the same side and crossed fibers of optic nerve from the opposite side. Fibers from fovea do not enter superior colliculus. Supraoptic nucleus of hypothalamus: It is concerned with the retinal control of pituitary in animals. But in human, it does not play any important role. Fibers from lateral geniculate body pass through internal capsule and form optic radiation.
Ref : Sembulingam 6th edition (Page- 990,991)

Explanation :
Lesion of left optic nerve: Total blindness of left eye.
Lesion of right optic nerve: Total blindness of right eye.
Lesion of lateral fibers in left side of optic chiasma: Left nasal hemianopia.
Lesion of lateral fibers in right side of optic chiasma: Right nasal hemianopia C + D.
Lesion of lateral fibers in both sides of optic chiasma: Binasal hemianopia.
Lesion of medial fibers in optic chiasma: Bitemporal hemianopia.
Lesion of left optic radiation: Right homonymous hemianopia.
Lesion of right optic radiation: Left homonymous hemianopia.nknown.

Ref : Sembulingam 6th edition (Figure-168.5)

Explanation :

Ref : Sembulingam 6th edition (Figure- 169.1)

Explanation : In addition to increase in anterior curvature of the lens, two more adjustments are made in the eyeball during accommodation for near vision.
1. Convergence of both eyeballs: It is necessary to bring the retinal images on to the corresponding points
2. Constriction of pupil: It is necessary to:
i. Increase the visual acuity by reducing lateral chromatic and spherical aberrations
ii. Reduce the quantity of light entering eye
iii. Increase the depth of focus through more central part of lens as its convexity is increased.
Ref : Sembulingam 6th edition (Page- 996)

Explanation : Neurons of dorsal and ventral cochlear nuclei in the medulla oblongata form the second order neurons of auditory pathway.
Ref : Sembulingum 6th edition (Page- 1013)

Explanation : Cortical auditory centers are in the temporal lobe of cerebral cortex. Auditory areas are:
1. Primary auditory area, which includes area 41, area 42 and Wernicke area.
2. Secondary auditory area or auditopsychic area, which includes area 22
Ref : Sembulingam 6th edition (Page- 1014)

Explanation : Type of Cells in Taste Bud
1. Type I cells or sustentacular cells
2. Type II cells
3. Type III cells
4. Type IV cells or basal cells.
Type I cells and type IV cells are supporting cells. Type III cells are the taste receptor cells. Function of type II cell is unknown.

Ref : Sembulingam 6th edition (Page- 1024)

Explanation : Center for taste sensation is in opercular insular cortex, i.e. in the lower part of postcentral gyrus, which receives cutaneous sensations from face. Thus, the taste fibers do not have an independent cortical projection.
Ref : Sembulingam 6th edition (Page- 1025)

Explanation : Receptor organ in semicircular canal is called crista ampullaris and that in otolith organ is called macula. These receptor organs contain the proprioceptors.
Ref : Sembulingam 6th edition (Page- 921)

Explanation : Superior semicircular canal gives response to rotation in anteroposterior plane (transverse axis). Horizontal semicircular canal gives response to rotation in horizontal plane (vertical axis). Semicircular canals are concerned with angular (rotatory) acceleration. Otolith organ is concerned with linear acceleration and detects acceleration in both horizontal and vertical planes. Utricle responds during horizontal acceleration and saccule responds during vertical acceleration.
Ref : Sembulingam 6th edition (Page- 924, 926)

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

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)

Explanation : Nissl bodies or Nissl granules are small basophilic granules found in cytoplasm of neurons and are named after the discoverer. These bodies are present in soma and dendrite but not in axon and axon hillock. Nissl bodies are called tigroid substances.
Ref : Sembullingam 6th edition (Page- 760)

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)

Explanation : All-or-none Law, Infatigability, Adaptation, Summation, Refractory period, Conductivity etc are the properties of a nerve fibre.
Ref : Sembulingam 6th edition (Page- 768, 769)

Ref : Sembulingam 6th edition (Table- 136.1)
Explanation : RMP of a nerve fibre is -70 mV, Firing level of a nerve fibre is -55 mv, End of depolarization of the nerve fibre is at +35 mV.

Ref : Sembulingam 6th edition (Table- 136.1)

Ref : Sembulingam 6th edition (Page- 770)
Explanation : First degree of injury is called Seddon neuropraxia. Second degree of injury is called axonotmesis. . Third, fourth and fifth degrees of injury are called neurotmesis.

Ref : Sembulingam 6th edition (Page- 770)

Explanation : Fibrous type of astrocytes play an important role in the formation of blood-brain barrier by sending processes to the blood vessels of brain, particularly the capillaries, forming tight junction with capillary membrane. Tight junction in turn forms the blood-brain barrier.
Ref : Sembulingam 6th edition (Page- 773, 774)

Explanation : Schwann cells Provide myelination (insulation) around the nerve fibers in PNS , Play important role in nerve regeneration , Remove cellular debris during regeneration by their phagocytic activity. Satellite cells Provide physical support to the PNS neurons , help in regulation of chemical environment of ECF around the PNS neurons.
Ref : Sembulingam 6th Edition (Page- 774)

Explanation :

Ref : Sembulingam 6th edition (Figure-139.2)

Explanation : EPSP is confined only to the synapse. It is a graded potential. It is similar to receptor potential and endplate potential. EPSP has two properties: 1. It is nonpropagated 2. It does not obey all or none law. EPSP is not transmitted into the axon of postsynaptic neuron. However, it causes development of action potential in the axon.
Ref : Sembulingam 6th edition (Page- 783)

Explanation : Presynaptic inhibition is mediated by axoaxonal synapses. It is prominent in spinal cord. Negative feedback inhibition is the type of synaptic inhibition, which is caused by Renshaw cells in spinal cord. Feedforward synaptic inhibition occurs in cerebellum and it controls the neuronal activity in cerebellum. Inhibition of antagonistic muscles when a group of muscles are activated is called reciprocal inhibition. It is because of reciprocal innervation.
Ref : Sembulingam 6th edition (Page- 783, 784)

Explanation : Normal duration of synaptic delay is 0.3 to 0.5 millisecond. Synaptic delay is one of the causes for reaction time of reflex activity.
Ref : Sembulingam 6th edition (Page- 785)

Explanation :

Ref : Sembulingam 6th edition (Table- 141.1)

Explanation :

Ref : Sembulingam 6th edition (Table- 141.1)

Explanation : Acetylcholine is the transmitter substance at the neuromuscular junction and synapse. It is also released by the following nerve endings:
1. Preganglionic parasympathetic nerve
2. Postganglionic parasympathetic nerve
3. Preganglionic sympathetic nerve
4. Postganglionic sympathetic cholinergic nerves:
  i. Nerves supplying eccrine sweat glands
  ii. Sympathetic vasodilator nerves in skeletal muscle
5. Nerves in amacrine cells of retina
6. Many regions of brain.

Ref : Sembulingam 6th edition (Page- 789)

Explanation :

Ref : Sembulingam 6th edition (Table- 141.3)

Explanation : Root value for Jaw jerk is Pons – V cranial nerve, Biceps jerk is C5, C6,Triceps jerk is C6 to C8 , Supinator jerk or radial periosteal reflex is C7, C8 ,Wrist tendon or finger flexion reflex is C8, T1, Knee jerk or patellar tendon reflex is L2 to L4, Ankle jerk or Achilles tendon reflex is L5 to S2.
Ref : Sembulingam 6th edition (Table-142.3)

Explanation : Superficial cutaneous reflexes are Scapular reflex, Upper abdominal reflex, Lower abdominal reflex, Cremasteric reflex, Gluteal reflex, Plantar reflex, Bulbocavernous reflex, Anal reflex.
Ref : Sembulingam 6th edition (Table- 142.2)

Explanation : Trigeminal nerve acts as afferent nerve in case of corneal,conjunctival & nasal superficial mucous membrane reflexes. Glossopharyngeal nerve acts as afferent nerve in case of uvular & pharyngeal reflex.
Ref : Sembulingam 6th edition (Table- 142.1)

Explanation : Pressure sensation,pain sensation,temparature sensation with wider range (below 25 degree celcius & above 40 degree celcius) are protopathic sensation. Epicritic sensations are: i. Fine touch or tactile sensation, ii. Tactile localization, iii. Tactile discrimination, iv. Temperature sensation with finer range between 25°C and 40°C.Visceral,vibratory & kinesthetic sensations are deep sensations.
Ref : Sembulingam 6th edition (Figure- 144.1)

Explanation :

Ref : Sembulingam 6th edition (Table-144.3)

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

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 : Anterior or Preoptic group- 1. Preoptic nucleus 2. Paraventricular nucleus 3. Anterior nucleus 4. Supraoptic nucleus 5. Suprachiasmatic nucleus
Middle or Tuberal group- 1. Dorsomedial nucleus 2. Ventromedial nucleus 3. Lateral nucleus 4. Arcuate (tuberal) nucleus
Posterior or Mamillary group- 1. Posterior nucleus 2. Mamillary body

Ref: Sembulingam 6th edition (Table- 149.1)

Explantion : Purkinje cells are termed as ‘final common path’ of cerebellar cortex. It is because the impulses from different parts of cerebellar cortex are transmitted to other parts of brain only through Purkinje cells.
Ref : Sembulingam 6th edition (Page- 866)

Explanation : Climbing & Mossy fibres,Granule cells are excitatory neuron in cerebellum.Stellate,basket,golgi & purkinje cells are inhibitory neuron of cerebellum.
Ref : Sembulingam 6th edition (Table-150.2)

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 : Functions of the cerebellum-
a. Vestibulocerebellum—control of balance and eye movement.
b. Pontocerebellum—planning and initiation of movement.
c. Spinocerebellum—synergy, which is control of rate, force, range, and direction of movement.

Ref : BRS Physiology 7th edition

Explanation : C fibers (slow pain) are the smallest nerve fibers and therefore have the slowest conduction velocity.
Ref : BRS Physiology 7th edition (Table-2.5)

Explanation : Coordination of movement (synergy) is the function of the cerebellum. Lesions of the cerebellum cause ataxia, lack of coordination, poor execution of movement, delay in initiation of movement, and inability to perform rapidly alternating movements. The premotor and motor cortices plan and execute movements. Lesions of the substantia nigra, a component of the basal ganglia, result in tremors, lead-pipe rigidity, and poor muscle tone (Parkinson disease).
Ref : BRS Physiology 7th edition