SWOT with Narayankar

any of a class of aromatic amines which includes a number of neurotransmitters such as adrenaline and dopamine.

 Adrenaline and norepinephrine (noradrenaline) are two closely related hormones that play key roles in your body's "fight or flight" response to stress or danger. 1. **Adrenaline (Epinephrine)**:    - Produced in the adrenal glands, which sit on top of your kidneys.    - It's like the body's emergency alarm – when you face a threat, adrenaline rushes into your bloodstream.    - Adrenaline increases your heart rate, widens airways, and boosts energy by releasing stored sugar.    - It helps you respond quickly to challenges, like running from danger or reacting to a sudden stressor. 2. **Norepinephrine (Noradrenaline)**:    - It's also produced in the adrenal glands and released as part of the stress response.    - Norepinephrine acts on your nervous system and blood vessels.    - It narrows blood vessels, increasing blood pressure and redirecting blood to vital areas during stress.    - Norepinephrine helps you stay alert and focused during challenging situatio

  Amines are a class of organic compounds that include various compounds, some of which can act as hormones. For example, epinephrine and norepinephrine are amines that function as hormones and neurotransmitters, playing a crucial role in the body's "fight or flight" response. These hormones are produced by the adrenal glands and have effects on heart rate, blood pressure, and other physiological responses. There are other amine hormones like serotonin and dopamine, which are neurotransmitters that influence mood and other brain functions.  

Hormones are the chemical messengers of the endocrine system. Hormones are the signals which adjust the body's internal working, together with the nervous system. Every multicellular organism has hormones. The cells which react to a given hormone have special receptors for that hormone. When a hormone attaches to the receptor protein a mechanism for signalling is started. The cell or tissue that gets the message is called the 'target'. Hormones only act on cells which have the right receptors.

 Perilymph and endolymph are two different fluids found in the inner ear, specifically in the cochlea, which is the part of the ear responsible for hearing and balance. 1. Perilymph:    - Perilymph is a clear, watery fluid that fills the scala vestibuli and scala tympani, which are two of the three chambers within the cochlea of the inner ear.    - It has a composition similar to that of cerebrospinal fluid and is rich in sodium ions.    - Perilymph helps transmit sound vibrations from the middle ear to the inner ear. When sound waves enter the ear, they cause vibrations in the tympanic membrane (eardrum), which are then transferred to the ossicles (small bones in the middle ear). The ossicles amplify and transmit these vibrations to the fluid in the cochlea, including the perilymph.    - The movement of perilymph initiates the stimulation of hair cells within the cochlea, which are responsible for converting mechanical vibrations into electrical signals that the brain can interpret as

 Rods and cones are two types of photoreceptor cells in the retina of the eye, and they play distinct roles in the process of vision: 1. Rods:    - Sensitivity to Light Levels: Rod cells are highly sensitive to low levels of light, making them essential for vision in dim or low-light conditions, such as nighttime or in dark environments. They are responsible for scotopic vision.    - Black and White Vision: Rods primarily detect shades of gray and are not capable of perceiving color. They provide the visual system with information about the brightness and contrast of objects.    - Peripheral Vision: Rods are primarily located in the peripheral regions of the retina, making them important for peripheral vision and detecting motion in the periphery of our visual field.    - Rhodopsin: Rod cells contain the photopigment rhodopsin, which is highly sensitive to light and quickly regenerates in low-light conditions, allowing for continuous function in dim light. 2. Cones:    - Color Vision:

Acetylcholine is a tiny chemical messenger in your body that helps your nerve cells communicate with muscles and other cells. When a nerve wants to tell a muscle to move, it releases acetylcholine. This chemical then travels to the muscle and makes it contract (squeeze) or relax. This is how your brain tells your muscles what to do, like when you want to lift your arm or smile. Acetylcholine is a key player in controlling your muscles and many other important processes in your body.

A ganglion is like a little bundle of nerve cells or neurons. These nerve cells are found in your nervous system, which is like your body's communication network. Ganglia (plural of ganglion) help in passing messages or signals between different parts of your body. Imagine ganglia as relay stations where information gets transferred. They're essential for coordinating things like moving your muscles, feeling sensations, and more. So, ganglia are like the switches and routers of your body's messaging system, helping everything work smoothly. Different types of ganglia: 1. Dorsal Root Ganglion: These ganglia are like entry points for sensory information. Imagine them as the doorstep to your nervous system. When you touch something hot or cold, the signals start here. They're like the body's alarm system. 2. Autonomic Ganglion: These ganglia handle the automatic, involuntary stuff your body does, like your heart beating or your digestion. Think of them as the control c

i. Each spinal nerve is formed inside the neural canal of vertebral column by two roots - the posterior or dorsal sensory root and anterior or ventral root. 11. Anterior root receives the sensory nerve from the dorsal root ganglion (cell bodies of sensory neurons are located in the ganglion), while the anterior/ventral root gives out the motor nerve. 111. The dorsal sensory and the ventral motor nerves together form the mixed spinal nerve. It emerges out from both sides of the spinal cord through the inter-vertebral foramen. iv. Spinal nerves emerging from vertebral column immediately divide into three branches, namely ramus dorsalis, ramus ventralis, and ramus communicans. a. Ramus dorsalis: from skin and to muscles of dorsal sure. b.Ramus ventralis: the largest of the three, supplies the organs and muscles on lateral and anterior side. c. Ramus communicans: the smallest of the three and given out from 1st thoracic up to 3rd lumbar (L3) spinal nerve. It joins the sympathet

i. The spinal cord is dorso-ventrally flattened due to the presence of deep, narrow posterior fissure and shallow, broad anterior fissure. The fissures divide the spinal cord incompletely into a right and left side. ii. The fissures divide the grey matter into six horns, namely dorsal, lateral and ventral horns while the white matter is divisible into 6 columns or funiculi, namely dorsal, lateral and ventral funiculi. iii. The H-shaped or butterfly shaped grey matter is on the inner side, while the white matter is on the outer side. iv. The dorsal and ventral horns extend out of the spinal cord as dorsal root and ventral root of spinal cord respectively. V. The dorsal root is connected to the dorsal root ganglion (lies just outside and lateral to the spinal cord). It has an aggregation/collection of unipolar sensory neurons. vi. A central canal can be seen in the centre. vii. The association or inter-neurons lie inside the grey matter. They receive signal from the sensory n

The posterior region of the brain is called hind brain. It consists of pons varolli, cerebellum and medulla oblongata. i. Pons varolli : a. It appears as a rounded bulge on the underside of the brain stem and contains a cross band of nerve fibres connecting cerebrum, cerebellar lobes, medulla oblongata and spinal cord. b. It also contains several nuclei. ii. Cerebellum : a. It is the second largest part of the brain and consists of two lateral hemispheres and a central vermis. b. It is composed of white matter with a thin layer of grey matter, the cortex. c.The white matter intermixes with the grey matter and shows a tree-like pattern called arbor vitae. d. The surface of cerebellum shows convolutions (gyri and sulci) a number of nuclei lie deep within each lateral or cerebellar hemisphere. e.Over 30 million neurons lie in the cortex. f. Three pairs of myelinated nerve bundles called cerebullar penduncles connect cerebellum to the other p

i. Midbrain is located between diencephalon(consists of epithalamus, thalamus & hypothalamus) and the pons varolli. ii. It contains the cerebral aqueduct or iter that connects the third and fourth ventricles. iii. The corpora quadrigemina are four rounded elevations on the dorsal surface of the mid brain. The two superior colliculi are involved in visual reflexes and the two inferior colliculi are relay centres for auditory reflexes that operate when it is necessary to move the head to hear sounds more distinctly. iv. The mid brain also contains on its inferior surface two thick fibrous tracks called cerebral peduncles or crura cerebri. V. The tracts of ascending and descending nerve fibres from RAS (Renin Angiotensin system) connect the cerebrum and mid brain. vi. Near the centre of the mid brain is a mass of grey matter scattered within the white matter. It is called the re

a. The electrical signals called brain waves are generated by neurons close to the brain surface, mainly neurons in the cerebral cortex which can be detected by sensors called electrodes. The electrodes are placed on the forehead and scalp. A record of such waves is called an electroencephalogram or EEG. b. EEG is useful in studying normal brain functions, such as changes that occur during sleep, and in diagnosing a variety of brain disorders, such as epilepsy, tumours, trauma, hematomas, metabolic abnormalities, sites of 10 trauma and degenerative diseases. The EEG is also utilized to establish or confirm that brain death has occurred.

Cerebrum shows three types of areas sensory, motor and association area. Following are the functional areas of cerebrum:  i. Frontal lobes: They have motor area which controls voluntary motor activities or movements of muscles. The centre for expression of emotions, intelligence, will power, memory, personality areas are located in the frontal lobe. The premotor area is higher centre for involuntary movements and autonomous nervous system. Association area is for coordination between sensation and movements. Broca's area /motor speech area is the motor speech area and translates thoughts into speech and controls movement of tongue, lips and vocal cords. ii. Parietal lobes: They are mainly for somaesthetic sensation of pain, pressure, temperature, tastes (gustatoreceptor). iii. Temporal lobes: It contains centres for smell (olfactory), hearing (auditory), speech and emotions. iv. Occipital lobes: They have visual area mainly for sense of vision. Wernicke'

i. Basal ganglia or basal nuclei are grey masses present within the white matter or lying on the lateral sides of thalamus. ii. The basal ganglia or nuclei of cerebrum receive neurotransmitters from various parts. iii. They help the cortex in the execution of activities at the subconscious level. e.g. Writing slow or rapid typing. iv. The largest basal nucleus known as corpus striatum, is located at the floor of cerebrum.

i. Frontal lobe: Involved in motor function, problem solving, judgement, impulse control, etc. ii. Parietal lobe Integrates sensory information, language processing, manages taste, hearing, smell, touch and sight, etc. iii. Occipital lobe Controlling vision, visual processing iv. Cerebellum Co-ordinates voluntary movements and maintains body balance V. Medulla Controls involuntary activities like - beating of the heart, blood circulation, breathing, sneezing, coughing, salivation, etc. vi. Temporal lobe Facial recognition, language comprehension, speech, memory, auditory perception, emotional responses and visual perception,etc.

i. Epithalamus: a. It is the thin non-nervous roof of the diencephalon. It is fused anteriorly with the pia mater to form the anterior choroid plexus. b. It is connected to pineal gland through a pineal stalk from its dorsal wall. ii. Thalamus: a. It is formed by lateral thick walls of diencephalon. Thalami mainly contain grey matter. b. The habenculor commissure connects two thalami. Different parts of the brain are interconnected by the RAS (Reticular Activating System) through the thalami. C. It is called relay centre as it transmits all sensory impulses except those of olfactory (smell) to the cerebrum. d. The narrow cavity of diencephalon is called 3rd ventricle or diocoel. It connects anteriorly to the two lateral ventricles by a single opening called Foramen of Monro and posteriorly to the 4th ventricle or metacoel through a narrow duct of Sylvius or iter. iii. Hypothalamus:  a. It is ectodermal in origin. b. It forms the floor of

 

i. The two cerebral hemispheres are internally connected to each other by a thick band of nerve fibres called corpus callosum . ii. Corpus callosum is typically seen in mammalian brain.  iii. It is the largest commissure of the brain.  iv. It has an anterior and posterior fold called genu and splenium respectively.

Forebrain consists of olfactory lobes, cerebrum and diencephalon.  i.   Olfactory lobes (Rhinencephalon): These highly reduced in human brain and covered by cerebrum from all sides except ventral. Each lobe consists of an olfactory peduncle and olfactory bulb. ii.  Cerebrum (Telencephalon):  a. It is a largest part of the brain, constituting about 85% of total brain.  b.It is divided into right and left cerebral hemispheres by means of a deep median, long fissure. The two hemispheres are internally connected to each other by corpus callosum .  C. The outer surface of cerebrum is called cerebral cortex , which has outer thin region composed of grey matter and the deep inner part is cerebral medulla , which is composed of white matter.  d.  The surface of each cerebral hemisphere is greatly folded by many convolutions or gyri and grooves called sulci . These greatly increase total surface area for accommo dation of the vast number of nerv