Apoptosis

 Apoptosis - programmed cell death 

Chick embryo developmental stages

 

Environmental biotechnology

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Ecological interactions - PPT

Exploring Ecological Interactions: Understanding the Complex Relationships in Ecosystems 🌿🦁

Presentation Overview:

Dive into the fascinating world of ecological interactions and discover the intricate relationships between organisms in ecosystems. This presentation covers key concepts, types, and examples of ecological interactions, including predation, competition, mutualism, commensalism, and parasitism.

Ecological interactions - PPT

 Explore the PPT to learn more about the complex and fascinating world of ecological interactions! 

Brain activity recording - EEG

 EEG -History

Electroencephalography is the measurement of electrical activity produced by the brain as recorded from the electrodes placed on the scalp. In 1875 Richard Caton from Germany discovered electrical activity of the brain by probing the surface of exposed brains (cerebral hemispheres) of animals such as Rabbits and Monkeys.

              In 1890 Adolf Beck, a Polish physiologist of Poland, Investigated the spontaneous electrical activity of the brains of rabbits and dogs. In 1920 Hans burger an Australian psychiatrist was the first to record EEG tracings from human beings. He discovered waves at 10 HZ

(Alpha waves were the first he isolated in the human EEG) .

              In 1935 Forester and Alteberger first used intra operative EEG. In 1950 Herbert jasper and

Wilder penfield developed ECoG for localisation and surgical treatment of epilepsy.

COMPONENTS OF EEG

1.Electrodes : small metal discs usually made of stainless steel ,tin,gold or silver covered with silver chloride coating. Placed on the scalp in a special position, this position is specified using the international 10/20 system. Each electrode site is labeled with a letter and a number , the letter refers to the area of the brain underlying the electrode. Even numbers denote the right side of the head and odd numbers denote the left side of the head.

2. Amplifier : it is an electronic device that increases the power of a signal. It does this by taking energy from a power supply and controlling the output to match the input signal shape but with a larger Amplitude. Human brain wave activity is too subtle to read unless the signal is amplified. These units are connected Through a USB port and transmit signals to the therapist computer.

3. Filters : The use of filters in recording and displaying EEG data is an indispensable tool in producing interpretable EEG tracings.Without filters, many segments of EEG would be essentially unreadable.The main benefit of filters is that they can appear to clean up the EEG tracing, making it easier to interpret and generally more pleasing to the eye.

4.Writing unit :The final link between the patient and legible EEG tracing is the writer. The writing unit may be replaced by a digital screen in modern EEG devices.

USES OF EEG

● To distinguish epileptic seizures from other types of spells such as Psychogenic nonepileptic seizures syncope ,Subcortical movement disorders and migraine variants.

● To characterize seizures for the purpose of treatment

● to localise the region of brain from which a seizure originates for work up of possible seizure surgery.

● To monitor for nonconvulsive seizures or nonconvulsive status epilepticus.

● To differentiate organic encephalopathy or delirium from primary psychiatric syndromes such as catatonia.

● Monitoring depth of anaesthesia

● As an indirect indicator of cerebral perfusion in carotid endarterectomy.

● To serve as an adjunct test of brain death.

● Determine the level of brain function in people who are in coma .

● Used to investigate other conditions such as head injuries, brain tumors, dementia, hemorrhage.

ADVANTAGES

EEG Has several strong sides as a tool for exploring brain activity; its time resolution is very high. EEG measures the brain’s Electrical activity directly while the other methods record changes in blood flow or metabolic activity indirect markers of brain electrical activity. It can be used simultaneously with FMRI so that high temporal resolution can be recorded at the same time as high spatial resolution data. EEG can be recorded at the same time as in MEG so that data from these complementary high time resolution techniques can be combined.

LIMITATIONS OF EEG

EEG has several limitations. Most important is its poor spatial resolution. EEG is most sensitive to a particular set of postsynaptic potentials. those which are generated in the superficial layers of the cortex on the crests of gyri directly abutting the skull and radial to the skull.Dendrites which are deeper in the cortex inside sulci are in midlane or deep structures or produce currents which are tangential to the skull have far less contribution to the EEG signal.The meninges, cerebrospinal fluid and skull smear the EEG signal obscuring its intracranial source.it is mathematically impossible to reconstruct a unique intracranial current source for a given EEG signal as some currents produse potentials that cancel each other out. This is an inverse problem.

CONCLUSION

Brain activity can be recorded by electroencephalography.it detects the abnormalities in brain waves.sometimes EEG is described as abnormal but does not specify the abnormality or disease.in general EEG is the best method to diagnose a disease and it is better than its alternatives for many reasons, and there are almost no low cost alternatives to EEG. Brain stimulation can be used to treat brain abnormalities such as Parkinson's disease,dystonia and psychiatric conditions.brain lesions are damages to brain cells.it is permanent condition so with medication can reduce the symptoms.through radiation therapy tumors are treated.

Lymph channels of the body - Formation and composition of lymph

LYMPH CHANNELS OF THE BODY

Lymphatic system consists of lymph channels such as lymph capillaries, collecting vessels, lymphatic trunks and lymphatic ducts. Lymph vessels are thin walled, valved vessels which carry lymph fluids. Lymphatic vessels begin as lymphatic capillaries, which combine to form lymphatic vessels. Lymphatic trunk is formed by joining of large lymphatic vessels. Lymphatic trunk is opens into two large lymphatic duct –

1. right lymphatic duct.

2. thoracic (left lymphatic)duct.

Lymph capillaries :

• made up of single layered endothelial cells.

• It contain minivalve- flap like structure formed by overlapping of adjacent endothelial cells. Minivalves allow lymph flow only in one direction (towards the thorax).

• Lymphatic capillaries are attached to the neighbouring tissue by anchoring filaments, that contain collagen filaments and elastic fibres.

• It has greater permeability than blood capillaries.

Lymphatic vessels

• Similar to veins

• It has 3 layers

1) Tunica intima – inner layer-made up of single squamous epithelium.

2) Tunica media—middle layer consist of smooth muscles n elastic tissue-arranged in circular shape around endothelium.

3) Adventitia – outer layer contain fibrous tissue.

• Afferent lymphatic vessels ➡️lymph node ➡️ Efferent lymphatic vessel.

Lymphatic trunk

• Lymphatic vessels exit lymph nodes and join to form lymphatic trunks.

• Major lymphatic trunks are

a) Lumbar trunks (right and left lumbar trunk)- drain lymph from lower limbs, wall n viscera of pelvis, kidneys, adrenal glands n abdominal wall.

b) Intestinal trunk – drains lymph from intestines, stomach, spIeen , part of liver n pancreas.

c) Broncho mediastinal trunks (right and left) –carry lymph from heart, thoracic wall n lung.

d) Subclavian trunks (right and left) –lymph from upper limbs.

e) Jugular trunks (right and left) -- drain lymph from head and neck.

Lymphatic duct

• Lymphatic ducts helps to return lymph fluid into blood.

• 2 lymphatic ducts of body are

1) Right lymphatic duct --- 1.2 cm length.

• Receives lymph from the right jugular, right subclavian, and right bronchomediastinal trunks.

• Drains lymph into venous blood at the junction of the right internal jugular and right subclavian veins.

2) .Thoracic duct/ left lymphatic duct -- larger duct - for lymph drainage from whole body except for right sides of head , neck ,thorax, and the right upper extremity.

• 38-45 cm long 2-5mm in diameter.

• It contains valves -- unicuspid, bicuspid( common), or tricuspid prevents backflow.

• It runs from superior part of cisterna chyli(enlarged lymph sac at the L2 vertebral level to lower spine, it receives lymph from right and left lumbar trunks and intestinal trunk).

• It receives lymph from cisterna chyli, left jugular, left subclavian, and left Broncho mediastinal trunks.

LYMPH NODES

• It is small, bean- shaped organ ,Located along lymph vessels.

• 1–25 mm length.

• Function as filtering and processing center of immune system.

• It filter lymph before it is returned to the blood.

• Nearly 600 lymph nodes in body , occur as groups.

 Lacteals- specialized lymphatic capillaries In small intestine. Which absorb dietary lipids into lymphatic vessels n at last into the blood.

 Chyle -- creamy white lymph -- deposition of lipids causes lymph leaking from the small intestine

 Tissues that lack lymphatic capillaries

 avascular tissues (cartilage, epidermis, and cornea of eye).

 central nervous system.

 Teeth.

 portions of the spleen.

 red bone marrow.

 endomysium of muscles n bones.

These tissues have minute interstitial channels called prelymphatics through this interstitial fluid can flow this fluid eventually enters into lymphatic vessels or, in the case of the brain, into the cerebrospinal fluid and then directly back into the blood.

FORMATION OF LYMPH

• Interstitial fluid is a precursor of prenodal lymph -produced by ultrafiltration of capillary microcirculation

• Starling principle state that microvascular ultrafiltration is determined by net balance b/w osmotic and hydrostatic pressure across microvascular endothelium.

• Pressure gradient between arterial and venous valves of capillary beds induce the fluid filtering from the arterial end into interstitial space and reabsorption into venous system.

• This concept is revised

• Osmotic and hydrostatic pressure provide low level of fluid filtration from microcirculation at both arterial and venous ends towards interstitial fluid.

• Fluids, proteins and small molecules pass through microvessels, it get filtered from microvessels into interstitium.

• This exchange occurs in glycocalyx – matrix of glycoproteins and glycosaminoglycan. It has a thickness of 50 to 500 nm. Present on the luminous surface of endothelium. Extend to intercellular cleft.

• Glycocalyx act as a sieve of different size.-it influences filtration rate.

 FACTORS EFFECTING LYMPH FORMATION

• Capillary pressure – if capillary Pressure increased formation of lymph increases.

• Permeability of capillary walls – when permeability increases then more tissue fluid will be form and that increases lymph formation.

• Rise in temperature increases capillary permeability- ⬆️ lymph formation.

• Reduced oxygen supply - increases capillary permeability- ⬆️ lymph formation.

• Increased metabolic activity increases lymph formation.

Notes (PDF) on Biogeographical zones of India

Exploring India's Diverse Biogeographical Zones 

Get ready to embark on a journey across India's rich and varied biogeographical zones! From the majestic Himalayas to the tropical Western Ghats, and from the arid deserts to the lush mangrove forests, each zone is home to unique and fascinating flora and fauna.

Key Highlights:

1. Overview of India's biogeographical zones

2. Characteristics and features of each zone

3. Diverse flora and fauna found in each zone.

Dive into the notes and discover the incredible biodiversity of India's biogeographical zones! 

 

Click here for pdf Biogeographical zones of India