NEET Biology: Unit 1 NEURAL CONTROL & COORDINATION

About this blog post:

NEET  exam will be conducted twice a year. And our TN Government has revised the higher secondary board sullabus as par with NEET syllabus.In this Blog Post, I have given a unit in Biology for NEET exam. Upcoming posts will include free study materials for other units of Biology,Physics and Chemistry. Students/ readers, please look for the updates regularly. Soon, I will provide materials for TAMIL MEDIUM students also. I request students to utilize my effort to clear NEET.

BIOLOGY FOR NEET & AIIMS

UNIT1

NEURAL CONTROL & COORDINATION

 

 

THE RESTING MEMBRANE POTENTIAL IN RESTING PHASE

• The potential difference(a charge) which exists the cell membrane of nerve cells is always  negative inside the cell with respect to the outside. The membrane is said to be polarised.
• The potential difference across the membrane at rest is called resting membrane potential and this is about 70mV(the negative sign indicates that inside the cell is negative with respect to the outside). Range:60mV to 85mV  

Important Points

1. In the Frog's brain, only 2 skull meninges are present. the middle meninge that is Arachnoid is absent.
2. In Rabbit, man and mammals, 3 skull meninges are present.
3. Increase in the amount of cerebro-spinal fluid is a diseased condition called HYDROCEPHALUS
4. "Meningitis":- It arises due to infection or inflammatory or injury in the meninges. Infection may be due to Virus or Bacteria or Both
5. PIAMATOR is the most vascular and conducting and it provide nutrition
6. The power of regeneration is Very Less in a Neuron.
7. the optic lobes of frog are hollow and in them OPTOCOEL cavity is found.
8. In frog, 2 Optic lobes are found. These are hollow and termed as Corpora -Bigemina. In mammals, 4 solid Optic lobes are present.
9. Around the brain of fishes, only one Menix is found. It's called "MENIX-Primitiva"
10.  The valve of Vieussens joins teh optic lobes with the Cerebellum.
11. Cerebral-Cortex is made up of gray matter and it is divided into 3 areas viz., Sensory area, Motor area and Associated area.
12. The sensory and associated areas determine the shape, colour, sound, taste and smell of any object.
13. Motor area regulates muscular contraction.
14. BROCA's area - Motor Speech Area
15. Broca's area is present in the lateral part of the frontal-lobe of the cerebrum. This area makes aware of languages and translates the written words into speech.
16. If Broca's area is deatroyed, the animal becomes unable to speak.
17. The temporal lobes of the cerebrum regulates the mechanism of hearing.
18. Cerebrum is the centre of the following: Intelligence, Emotion, Will-Power, Memory, Conciousness, Experience, Knowledge, Voluntary Control, Laughing and Weeping, Defecation & Micturition.
19. Diencephalon is the center of carbohydrate-metabolism and fat-metabolism.
20. In Rabbit, SWAMMERDAM's GLAND are absent. These glands are at the origin place of spinal nerves invertebrates and found in frogs. It provide extra supply of Ca++ for synaptic transmission.
21. Cerebellum made up of 3 layers and in the middle of cerebellum of brain lobes, falsk shaped cells are found called"PURKINJE-CELLS"
22. In the nerve cells, "Centrostromes" are absent. So once formed in development, teh nerve cells do not divide and remain in Inter Phase stage throughout their life. And grow in size with the growth of the body.
23. The velocity of nerve impulse is 5-50times more faster in Myelinated nerve fibres than Non-Myelinated nerve fibres.
24. In mammals, the speed of nerve fibres is 100-130m/sec (Maximum). In Frogs, the speed of nerve impulse is 30m/sec. In reptiles, the speed is 15-35m/sec.
25. Acytylcholinesterase enzyme helps in dissociation of Acytylcholine.
26. In the form of inhibitory beuro hormones, -GABA are present.(Gamma Amino Butyric Acid)

TIPS & FARMULA

• Coordination: It's the process through which two or more organs interact and complements the functions of one another.
• Integrated System: In human body, the neural system and the endocrine system jointly coordinate and integrate all the activities of the organs so that, they function in a synchronised fashion and inter dependent to each other, combinely called " the Integrated System"
• Neural system provides an organised network of point to point connections for a quick response(Fast Speed) and short span of coordination where as the endocrine system provides  chemical integration, slow speed and long lasting effect.
• Neurons:  The neural system of all animals are composed of highly specialised cells NEURONS, they are also known as Structural and Functional unit of Nervous system.
• 3 major parts of Neiron are DENDRON, CYTON & AXON.
• Nissl's granules: the cell body contains cytoplasm with typical cell organells & certain granular bodies called Nissl's granules (present in DENDRITES also)
• Limbic System: Complex stucture includes inner parts of cerebral hemisphere and associated deep stuctures like AMYGDALA & HIPPOCAMPUS. Along with hypothalamus, it is involved in olfaction, automation of response, regulation of sexual behaviour, expression of emotional reaction(Anger, Pleasure,  Rage, Fear,etc.,) and Motivation.
• Cranial Meninges: Inside Skull, brain is covered by Meninges, consisting of Outer Duaramater, Midddle Arachnoid and Inner Piamater.
• Cerebral hemispheres: A deep cleft divided the cerebrum longitudinally into 2 halves. termed as the left & right cerebral hemisphere.
• Corpus Callosum:Cerebral Hemispheres are connected by a tract of nerve fibre called Corpus Collasum
• Cerebral cortex: Layer of cells which covers the cerebral hemisphere, thrown into prominent folds.
• Gray Matter: Cerebral cortex is the grey matter due to greyish appearance and highly concentrated neuron cell bodies.
• White Matter: Fibres of the tract are covered with Myelin sheath that constitutes the inner part of cerebral hemispheres and gives opaque white appearance to the layer
• Association area: Cerebral cortex contains motor area, sensory area and large regions called association area, responsible for complex functions like, Inter sensory association, Memory & communication
• Neural system coordinates & Intergrates function as well as Metabolic activities  of the organs, generation and conduction of nerve impulse.
• Excitable cells: Neurons, Their membranes are in a polarized state due to concentrated gradients of ions across the membrane. Different types of ion channels are present oon neuronal membrane for which thie membrane is "selectively" Permeable.
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