Biology teacher

  Mechanism of Hormone Action – Easy NEET Notes Introduction Hormones regulate different physiological activities of the body. Based on their chemical nature, hormones are divided into four groups. Types of Hormones 1. Peptide / Polypeptide / Protein Hormones Examples Insulin Glucagon Pituitary hormones Hypothalamic hormones Important Features Made up of amino acids. Water soluble. Cannot pass through cell membrane. Act through membrane-bound receptors. NEET Point These hormones use second messengers like: cAMP IP₃ Ca²⁺ 2. Steroid Hormones Examples Cortisol Testosterone Estradiol Progesterone Important Features Lipid soluble. Can easily pass through plasma membrane. Receptors are inside the cell. NEET Point They directly influence: Gene expression Protein synthesis 3. Iodothyronines (Thyroid Hormones) Examples T₃ (Triiodothyronine) T₄ (Thyroxine) Important Features Derived from amino acid tyrosine. Regulate metabolism and ...

  19.3 Hormones of Heart, Kidney and Gastrointestinal Tract Easy NEET Notes (Line-by-Line Explanation) Introduction Original Idea: Some tissues other than endocrine glands also secrete hormones. Easy Explanation: We usually study hormones secreted by endocrine glands like pituitary, thyroid, adrenal etc. But some other organs and tissues also produce hormones. These hormones help in regulating important body functions. Hormones of Heart Atrial Natriuretic Factor (ANF) Line: “The atrial wall of our heart secretes a peptide hormone called atrial natriuretic factor (ANF).” Explanation: The atria are the upper chambers of the heart. Their walls produce a hormone called ANF . ANF is a peptide hormone (made of amino acids). Function of ANF Line: “ANF decreases blood pressure.” Explanation: ANF helps to lower high blood pressure. It maintains normal blood circulation. Line: “When blood pressure is increased, ANF is secreted which causes dilation of blo...

  19.2.9 Testis — Easy NEET Notes  - Dr.Sanjaykumar pawar Location of Testis Testes are present in the scrotal sac . The scrotal sac lies outside the abdomen in males. Lower temperature in the scrotum helps in sperm formation . Important Point Testis acts as: Primary sex organ → produces sperm Endocrine gland → secretes hormones Structure of Testis 1. Seminiferous Tubules Coiled tube-like structures inside testis. Main site of spermatogenesis (formation of sperms). 2. Stromal / Interstitial Tissue Tissue present between seminiferous tubules. Contains Leydig cells . Leydig Cells (Interstitial Cells) Found in intertubular spaces. Produce male sex hormones called androgens . Main androgen = Testosterone . NEET Fact LH hormone from pituitary stimulates Leydig cells to produce testosterone. Functions of Androgens (Testosterone) 1. Development of Male Reproductive Organs Androgens help in growth and maturation of: Epididymis Vas defere...

  Forebrain, Midbrain and Hindbrain – Easy NEET Notes 18.4.1 Forebrain Forebrain consists of: Cerebrum Thalamus Hypothalamus These are the major parts of the forebrain. Cerebrum Cerebrum is the largest part of the human brain . It controls: Thinking Intelligence Memory Learning Speech Voluntary actions Cerebral Hemispheres A deep groove divides the cerebrum into: Left cerebral hemisphere Right cerebral hemisphere Corpus Callosum Both hemispheres are connected by nerve fibres called: Corpus callosum It allows communication between the two hemispheres. Cerebral Cortex Outer layer of cerebrum is called the cerebral cortex . It is highly folded to increase surface area. It appears grey due to presence of neuron cell bodies. Therefore, it is called Grey Matter . Functions of Cerebral Cortex It contains: Motor areas → control voluntary movements. Sensory areas → receive sensory impulses. Association areas → involved in: Memory Inte...