A human cell consists of several key structures, each with a specific function. Here’s a breakdown of the main parts of a human cell and their functions:

1. Cell Membrane (Plasma Membrane)

• Function: Acts as a barrier to protect the cell, regulating what enters and exits the cell. It allows the passage of nutrients, water, and waste, while preventing harmful substances from entering.
• Special Feature: Made of a phospholipid bilayer with embedded proteins, it has selective permeability and contains receptors for communication with other cells.

2. Cytoplasm

• Function: The jelly-like fluid inside the cell that holds all the cell’s organelles in place. It provides a medium for biochemical reactions to occur.
• Special Feature: Contains enzymes that help in breaking down waste and metabolic processes.

3. Nucleus

• Function: The control center of the cell that contains the genetic material (DNA) and coordinates activities like growth, metabolism, protein synthesis, and reproduction (cell division).
• Special Feature: Surrounded by a nuclear envelope with pores that allow selective exchange of materials (like RNA and proteins) between the nucleus and cytoplasm.
• Parts of the Nucleus:
  • Nuclear Envelope: Double membrane that protects the nucleus.
  • Nuclear Pores: Allow passage of molecules like RNA and ribosomal subunits.
  • Nucleolus: Found inside the nucleus, it is involved in producing ribosomes.
  • Chromatin: DNA and protein complex that condenses into chromosomes during cell division.

4. Mitochondria

• Function: Known as the powerhouse of the cell, they generate energy in the form of adenosine triphosphate (ATP) through cellular respiration.
• Special Feature: They have their own DNA and can replicate independently. Mitochondria are especially abundant in energy-demanding cells like muscle cells.

5. Ribosomes

• Function: Protein synthesis takes place in ribosomes. They read mRNA and assemble amino acids into proteins based on genetic instructions.
• Special Feature: Ribosomes can be free-floating in the cytoplasm or attached to the endoplasmic reticulum (forming rough ER).

6. Endoplasmic Reticulum (ER)

• Function: The ER is involved in the production, folding, and transport of proteins (rough ER) and lipids (smooth ER).
• Types:
  • Rough Endoplasmic Reticulum (Rough ER): Studded with ribosomes, it synthesizes and folds proteins destined for membranes or secretion.
  • Smooth Endoplasmic Reticulum (Smooth ER): Lacks ribosomes, involved in lipid synthesis, detoxification of drugs, and calcium storage.

7. Golgi Apparatus (Golgi Body)

• Function: The cell’s post office, it modifies, sorts, and packages proteins and lipids for transport to various destinations, including outside the cell.
• Special Feature: Composed of flattened membranous sacs called cisternae.

8. Lysosomes

• Function: Contain digestive enzymes to break down waste, cellular debris, and invading pathogens. They are involved in cellular recycling (autophagy).
• Special Feature: Often called the “clean-up crew” of the cell, they break down worn-out cell components.

9. Peroxisomes

• Function: Involved in breaking down fatty acids and detoxifying harmful substances, such as hydrogen peroxide, into harmless water and oxygen.
• Special Feature: They contain oxidative enzymes that detoxify harmful substances and neutralize free radicals.

10. Cytoskeleton

• Function: Provides structural support to the cell, maintains its shape, and facilitates movement of the cell and its organelles.
• Parts of the Cytoskeleton:
  • Microfilaments: Made of actin, they help in cell movement and division.
  • Intermediate Filaments: Provide mechanical support for the cell.
  • Microtubules: Hollow tubes that help maintain cell shape, assist in cell division (mitosis), and enable the movement of organelles inside the cell.

11. Centrosomes and Centrioles

• Function: Centrosomes organize microtubules and regulate cell division. They play a critical role in forming the mitotic spindle, which separates chromosomes during cell division.
• Special Feature: Each centrosome contains a pair of centrioles that help in organizing microtubules in the cell during mitosis.

12. Vesicles

• Function: Small membrane-bound sacs that transport materials between organelles or between the cell and its exterior.
• Types:
  • Transport Vesicles: Move proteins from the ER to the Golgi apparatus.
  • Secretory Vesicles: Move proteins and lipids from the Golgi apparatus to the cell membrane for release outside the cell.

13. Vacuoles

• Function: Store nutrients, waste products, and help maintain osmotic balance in the cell. In plant cells, a large central vacuole stores water and helps maintain structural support.
• Special Feature: In animal cells, vacuoles are smaller and are involved in waste disposal.

14. Plasmodesmata (in Plant Cells)

• Function: Channels between plant cells that allow the passage of molecules and communication between neighboring cells.
• Special Feature: Enable the transport of materials like ions and hormones between adjacent plant cells.

15. Cilia and Flagella

• Function: Involved in cell movement. Cilia are short, hair-like structures that move fluids or mucus across the cell surface (in respiratory cells), while flagella are long, whip-like structures that propel cells (e.g., sperm cells).
• Special Feature: Powered by motor proteins, they are made of microtubules arranged in a “9+2” structure.

Summary

• Cell Membrane: Protects the cell and controls what goes in/out.
• Cytoplasm: Jelly-like fluid that supports organelles.
• Nucleus: The control center of the cell.
• Mitochondria: Powerhouse that produces energy.
• Ribosomes: Sites of protein synthesis.
• Endoplasmic Reticulum: Processes and transports proteins (Rough ER) and lipids (Smooth ER).
• Golgi Apparatus: Modifies, packages, and ships proteins and lipids.
• Lysosomes: Digest and recycle cellular waste.
• Peroxisomes: Detoxify harmful substances.
• Cytoskeleton: Provides structural support and mobility.
• Centrosomes/Centrioles: Organize cell division.
• Vesicles and Vacuoles: Storage and transport of substances.
• Cilia/Flagella: Involved in cell movement.

1. Red Blood Cells (Erythrocytes)
   • Function: Transport oxygen from the lungs to the body tissues and carry carbon dioxide back to the lungs for exhalation.
   • Special Feature: Contains hemoglobin, a protein that binds oxygen, and has a biconcave shape to increase surface area for gas exchange.
2. White Blood Cells (Leukocytes)
   • Function: Defend the body against infections and foreign invaders.
   • Types: Include neutrophils (engulf bacteria), lymphocytes (produce antibodies), monocytes (become macrophages), eosinophils (attack parasites), and basophils (release histamine in allergic reactions).
3. Platelets (Thrombocytes)
   • Function: Aid in blood clotting by clumping and forming plugs in blood vessel injuries.
   • Special Feature: Small cell fragments that lack a nucleus but play a critical role in preventing bleeding.
4. Nerve Cells (Neurons)
   • Function: Transmit electrical signals throughout the body to coordinate voluntary and involuntary actions.
   • Special Feature: Have long extensions called axons and dendrites that help in communication with other neurons, muscles, or glands.
5. Muscle Cells (Myocytes)
   • Function: Contract to produce movement.
   • Types: Skeletal muscle cells (voluntary movement), cardiac muscle cells (heartbeat), and smooth muscle cells (involuntary control in organs like intestines and blood vessels).
6. Epithelial Cells
   • Function: Form protective barriers on surfaces such as skin, lining of the gut, and respiratory passages.
   • Special Feature: Tightly packed cells that also aid in absorption, secretion, and sensation.
7. Adipocytes (Fat Cells)
   • Function: Store energy in the form of fat (lipids) and provide insulation and cushioning to organs.
   • Special Feature: Can expand or shrink depending on the body’s energy needs.
8. Bone Cells (Osteocytes, Osteoblasts, Osteoclasts)
   • Function: Support and protect the body by forming the skeleton; osteoblasts build bone, osteoclasts break down bone, and osteocytes maintain bone tissue.
   • Special Feature: Found embedded in a rigid matrix of calcium phosphate that gives bones their strength.
9. Stem Cells
   • Function: Undifferentiated cells that have the potential to develop into various cell types, enabling tissue growth and repair.
   • Special Feature: Can self-renew and differentiate into specialized cells, such as nerve, muscle, or blood cells.
10. Endothelial Cells
    • Function: Line blood vessels and regulate the exchange of materials between the bloodstream and surrounding tissues.
    • Special Feature: Play a key role in vascular health, inflammation, and blood pressure regulation.
11. Germ Cells (Sperm and Egg Cells)
    • Function: Responsible for reproduction; sperm fertilizes the egg, leading to the development of a new organism.
    • Special Feature: Carry half the genetic information (haploid) necessary for creating offspring.
12. Pancreatic Cells (Islet Cells)
    • Function: Produce hormones like insulin (regulates blood sugar levels) and glucagon.
    • Special Feature: Specialized cells in the pancreas that play a critical role in glucose metabolism.

Each cell type in the human body is specialized to perform specific functions, ensuring the proper functioning of various organs and systems.

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Here are additional human cell types and their functions:

13. Fibroblasts
    • Function: Produce collagen and other fibers to form the extracellular matrix, which provides structural support to tissues.
    • Special Feature: Play a key role in wound healing by generating connective tissue that helps repair damaged areas.
14. Chondrocytes (Cartilage Cells)
    • Function: Produce and maintain the cartilaginous matrix, which is essential for cushioning joints.
    • Special Feature: Found in the cartilage and responsible for maintaining the structure and flexibility of cartilage tissue.
15. Goblet Cells
    • Function: Secrete mucus in the respiratory and digestive tracts to trap particles and protect underlying cells from damage.
    • Special Feature: Shaped like a goblet, they are specialized for secretion of mucins that form mucus.
16. Macrophages
    • Function: Engulf and digest pathogens, dead cells, and other debris in the body.
    • Special Feature: Act as a key component of the immune system by presenting antigens to T cells, initiating an immune response.
17. Lymphocytes (B and T Cells)
    • Function: B cells produce antibodies that neutralize pathogens, while T cells kill infected cells and help regulate immune responses.
    • Special Feature: Critical in adaptive immunity, capable of remembering pathogens for quicker responses during future infections.
18. Hepatocytes (Liver Cells)
    • Function: Perform various functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion (e.g., bile).
    • Special Feature: Highly active in metabolism, processing nutrients, and breaking down toxins and drugs.
19. Melanocytes
    • Function: Produce melanin, the pigment responsible for skin, hair, and eye color.
    • Special Feature: Located in the skin’s basal layer, they protect against ultraviolet (UV) radiation by absorbing harmful rays.
20. Acinar Cells
    • Function: Produce digestive enzymes in the pancreas, which are secreted into the small intestine to aid in the breakdown of food.
    • Special Feature: Specialized for the secretion of digestive enzymes like lipase, protease, and amylase.
21. Schwann Cells
    • Function: Form the myelin sheath around nerve fibers in the peripheral nervous system, aiding in the rapid transmission of nerve impulses.
    • Special Feature: Provide insulation to axons, allowing electrical signals to travel efficiently.
22. Oligodendrocytes
    • Function: Similar to Schwann cells but located in the central nervous system (brain and spinal cord), they create the myelin sheath around neurons.
    • Special Feature: Enable faster conduction of electrical signals by insulating axons in the brain and spinal cord.
23. Astrocytes
    • Function: Support neurons by providing nutrients, maintaining the blood-brain barrier, and regulating ion balance in the brain.
    • Special Feature: Star-shaped glial cells found in the central nervous system, crucial for maintaining a stable environment for neurons.
24. Microglia
    • Function: Act as the brain’s immune cells, scavenging dead cells, pathogens, and cellular debris.
    • Special Feature: Have the ability to morph and move to areas of damage or infection in the central nervous system, playing a role in neuroinflammation.
25. Langerhans Cells
    • Function: Specialized dendritic cells found in the skin, responsible for capturing and presenting antigens to T cells, thus initiating an immune response.
    • Special Feature: Act as immune sentinels in the epidermis, detecting and responding to infections.
26. Keratinocytes
    • Function: Produce keratin, a protein that strengthens the skin, hair, and nails.
    • Special Feature: Constitute the majority of cells in the epidermis and are essential for the skin’s protective barrier.
27. Podocytes
    • Function: Specialized cells in the kidneys that wrap around capillaries of the glomerulus, aiding in the filtration of blood to form urine.
    • Special Feature: Their finger-like projections (foot processes) form filtration slits that prevent large molecules, like proteins, from entering the urine.
28. Endocrine Cells
    • Function: Produce and secrete hormones into the bloodstream to regulate various bodily functions, such as metabolism, growth, and reproduction.
    • Special Feature: Found in glands like the thyroid, pituitary, and adrenal glands, and control key physiological processes through hormonal signaling.
29. Retinal Cells (Photoreceptor Cells)
    • Function: Detect light and convert it into electrical signals, which are then sent to the brain to form visual images.
    • Types: Rods (responsible for vision in low light) and cones (responsible for color vision and detail).
    • Special Feature: Located in the retina of the eye, they are essential for the sense of sight.
30. Smooth Muscle Cells
    • Function: Involuntarily contract to facilitate movements in organs such as the digestive tract, blood vessels, and airways.
    • Special Feature: Unlike skeletal muscles, smooth muscle cells are not under conscious control and sustain prolonged contractions.
31. Beta Cells (Pancreatic Cells)
    • Function: Produce and secrete insulin, which lowers blood sugar levels by facilitating glucose uptake into cells.
    • Special Feature: Located in the islets of Langerhans in the pancreas, critical for regulating blood glucose levels and energy metabolism.

These additional cell types demonstrate the complexity and diversity of human cells, each specialized for distinct roles in maintaining homeostasis and supporting overall health and function.

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Here are additional human cell types with their functions:

32. Basal Cells
    • Function: Act as stem cells in certain tissues, like the skin and respiratory tract, to replace dead or damaged cells.
    • Special Feature: Found in the lower layers of the epidermis and in epithelial tissues, they continuously divide to regenerate the tissue.
33. Ciliated Cells
    • Function: Help move fluids, mucus, or particles across the surface of epithelial tissues, particularly in the respiratory tract and fallopian tubes.
    • Special Feature: Covered with tiny hair-like projections called cilia that beat in a coordinated fashion to clear debris or aid in movement.
34. Kupffer Cells
    • Function: Specialized macrophages found in the liver, responsible for clearing bacteria, worn-out red blood cells, and toxins from the blood.
    • Special Feature: Reside within the liver sinusoids and play a critical role in filtering the blood and maintaining immune balance in the liver.
35. Granulocytes
    • Function: A type of white blood cell that fights infections. They include neutrophils (attack bacteria), eosinophils (combat parasites), and basophils (involved in allergic responses).
    • Special Feature: Contain granules filled with enzymes that are released to destroy pathogens or participate in inflammation.
36. Megakaryocytes
    • Function: Large bone marrow cells that produce platelets, which are essential for blood clotting.
    • Special Feature: They fragment into thousands of platelets, which circulate in the bloodstream to help with wound repair.
37. Merkel Cells
    • Function: Sensory cells in the skin involved in the perception of light touch and texture.
    • Special Feature: Found in the basal layer of the epidermis, they are connected to nerve endings and play a role in the sense of touch.
38. Retinal Pigment Epithelial Cells (RPE)
    • Function: Support the photoreceptors in the eye by absorbing excess light, nourishing the cells, and maintaining the visual cycle.
    • Special Feature: These cells form a barrier and serve critical functions for retinal health, including removing waste products from photoreceptor cells.
39. Purkinje Cells
    • Function: Large neurons found in the cerebellum that help coordinate motor movements by transmitting signals to other neurons.
    • Special Feature: Have a unique tree-like structure of dendrites that enables them to receive a large amount of input from other neurons.
40. Interstitial Cells of Leydig
    • Function: Produce testosterone, the primary male sex hormone, which is essential for male reproductive development and function.
    • Special Feature: Located in the testes, they are regulated by luteinizing hormone (LH) from the pituitary gland.
41. Oocytes (Egg Cells)
    • Function: Female reproductive cells that, when fertilized by sperm, develop into an embryo.
    • Special Feature: The largest human cells, they contain half the genetic material needed to form a new organism and contribute to the early stages of embryonic development.
42. Sertoli Cells
    • Function: Support and nourish developing sperm cells (spermatogenesis) in the testes.
    • Special Feature: Act as “nurse” cells by providing physical support, nutrients, and a regulated environment for sperm maturation.
43. Mast Cells
    • Function: Play a central role in allergic reactions by releasing histamine and other chemicals during immune responses.
    • Special Feature: Found in connective tissues and mucosal surfaces, they are involved in inflammation and can trigger symptoms such as swelling, itching, and bronchoconstriction.
44. Dendritic Cells
    • Function: Present antigens to T cells in the immune system, helping initiate an adaptive immune response.
    • Special Feature: They capture antigens from pathogens, process them, and present them on their surface to T cells, acting as a bridge between innate and adaptive immunity.
45. Enterocytes
    • Function: Absorb nutrients and electrolytes from the small intestine into the bloodstream.
    • Special Feature: Found in the lining of the intestines, they have microvilli on their surface that increase the surface area for absorption of nutrients.
46. Odontoblasts
    • Function: Produce dentin, the substance beneath the enamel of teeth, helping to maintain tooth structure and health.
    • Special Feature: Located in the pulp of the tooth, they play a crucial role in tooth development and repair.
47. Parietal Cells
    • Function: Secrete hydrochloric acid (HCl) in the stomach, which is necessary for digestion and activation of digestive enzymes like pepsin.
    • Special Feature: Found in the stomach lining, they help maintain the acidic environment needed for digestion.
48. Chief Cells
    • Function: Secrete pepsinogen, an inactive precursor to the enzyme pepsin, which helps digest proteins in the stomach.
    • Special Feature: Work in conjunction with parietal cells to facilitate the digestive process.
49. Sebaceous Gland Cells
    • Function: Produce sebum, an oily substance that lubricates the skin and hair, helping to keep them hydrated and protected from bacteria.
    • Special Feature: Found in the skin’s sebaceous glands, typically associated with hair follicles.
50. Myoblasts
    • Function: Precursor cells that develop into muscle fibers during growth or repair.
    • Special Feature: Can proliferate and differentiate into mature muscle cells, aiding in muscle growth and regeneration after injury.
51. Type I and Type II Pneumocytes
    • Function: Type I pneumocytes allow gas exchange in the lungs, while Type II pneumocytes produce surfactant, which reduces surface tension and prevents lung collapse.
    • Special Feature: Found in the alveoli of the lungs, Type I cells are thin for efficient gas diffusion, while Type II cells secrete surfactant to maintain lung function.
52. Ependymal Cells
    • Function: Line the ventricles of the brain and spinal cord, helping circulate cerebrospinal fluid (CSF) and creating a barrier between the fluid and nervous tissue.
    • Special Feature: These glial cells are involved in the production and circulation of CSF, providing cushioning and nutrient support to the brain.
53. Clara Cells (Club Cells)
    • Function: Detoxify harmful substances in the respiratory tract and produce components of surfactant that protect the lungs.
    • Special Feature: Found in the bronchioles of the lungs, they play a role in maintaining respiratory health by secreting protective proteins and enzymes.
54. Alveolar Macrophages
    • Function: Clear inhaled particles, bacteria, and dead cells from the alveoli in the lungs.
    • Special Feature: Act as the lungs’ immune defense by engulfing and digesting foreign substances.

These additional cell types showcase the specialized roles that cells play in different systems of the body, contributing to overall health, immunity, and the proper functioning of organs.

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Here are more human cell types and their functions without repetition:

55. Granulosa Cells
    • Function: Support the developing oocyte (egg cell) and produce hormones, primarily estrogen, in the ovarian follicle.
    • Special Feature: These cells surround the oocyte and are crucial for follicle maturation and reproductive hormone production.
56. Theca Cells
    • Function: Produce androgens (precursors to estrogen) in the ovaries and support follicle development.
    • Special Feature: Work alongside granulosa cells to regulate the hormonal environment necessary for ovulation.
57. Pericytes
    • Function: Regulate blood flow and contribute to the stability and integrity of blood vessels, especially capillaries.
    • Special Feature: Found wrapped around endothelial cells in capillaries, pericytes help in blood vessel formation and repair.
58. Microfold Cells (M Cells)
    • Function: Capture antigens from the gut lumen and present them to immune cells, initiating an immune response.
    • Special Feature: Located in the gut-associated lymphoid tissue (GALT), they play a key role in intestinal immune surveillance.
59. Juxtaglomerular Cells
    • Function: Regulate blood pressure by secreting renin, which helps control the constriction of blood vessels and water retention.
    • Special Feature: Found in the kidneys near the glomerulus, they are key to maintaining proper kidney function and blood pressure homeostasis.
60. Mesangial Cells
    • Function: Provide structural support for the glomeruli in the kidneys, regulate blood flow, and help filter blood plasma.
    • Special Feature: Located in the renal glomeruli, they contract to control blood flow through the capillaries and remove trapped residues from filtration.
61. Paneth Cells
    • Function: Secrete antimicrobial peptides and proteins in the intestines to protect against microbial infections.
    • Special Feature: Found in the small intestine, Paneth cells are vital for maintaining intestinal homeostasis by keeping harmful bacteria in check.
62. Trophoblasts
    • Function: Form the outer layer of the blastocyst, which becomes the placenta, and provide nutrients to the developing embryo.
    • Special Feature: Play a key role in implantation and forming the placenta, allowing nutrient and gas exchange between the mother and the fetus.
63. Retinal Ganglion Cells
    • Function: Transmit visual information from the retina to the brain via the optic nerve.
    • Special Feature: The final output neurons of the retina, they collect signals from photoreceptors and pass them to the brain for visual processing.
64. Brunner’s Gland Cells
    • Function: Secrete an alkaline mucus that protects the lining of the small intestine from acidic stomach contents.
    • Special Feature: Found in the duodenum, these cells play a crucial role in neutralizing stomach acid and creating an optimal pH for digestion.
65. Follicular Cells (Thyroid)
    • Function: Produce and secrete thyroid hormones (T3 and T4) that regulate metabolism, growth, and development.
    • Special Feature: Found in the thyroid gland, these cells respond to thyroid-stimulating hormone (TSH) from the pituitary to regulate energy metabolism.
66. Chief Cells (Parathyroid)
    • Function: Secrete parathyroid hormone (PTH), which regulates calcium levels in the blood.
    • Special Feature: Found in the parathyroid glands, these cells are essential for maintaining proper bone health and calcium homeostasis.
67. Myofibroblasts
    • Function: Involved in wound healing by contracting to close the wound and producing collagen to form scar tissue.
    • Special Feature: Combine features of fibroblasts and smooth muscle cells, playing a central role in tissue repair after injury.
68. Enteroendocrine Cells
    • Function: Release hormones like gastrin, secretin, and cholecystokinin to regulate digestion and other gut functions.
    • Special Feature: Found scattered throughout the gastrointestinal tract, they act as sensors of the gut environment and help coordinate digestive processes.
69. Parafollicular Cells (C Cells)
    • Function: Secrete calcitonin, a hormone that helps regulate calcium levels by reducing calcium concentration in the blood.
    • Special Feature: Located in the thyroid gland, these cells counterbalance the effects of parathyroid hormone (PTH) on calcium metabolism.
70. Pyramidal Cells (Cerebral Cortex)
    • Function: Involved in higher cognitive functions, such as thinking, decision-making, and controlling voluntary movement.
    • Special Feature: Large neurons with pyramid-shaped cell bodies, found in the cerebral cortex, they are important for synaptic communication in the brain.
71. Erythropoietic Cells
    • Function: Precursors to red blood cells (erythrocytes), responsible for generating new red blood cells in the bone marrow.
    • Special Feature: Differentiate into mature red blood cells in response to erythropoietin, a hormone that stimulates red blood cell production.
72. Satellite Cells (Muscle)
    • Function: Assist in the repair and regeneration of skeletal muscle by activating and differentiating into muscle fibers after injury.
    • Special Feature: Remain quiescent (inactive) in healthy muscle but proliferate and repair damaged muscle tissue when needed.
73. Centroacinar Cells
    • Function: Found in the pancreas, they contribute to the production of bicarbonate-rich fluid to neutralize stomach acid.
    • Special Feature: Located at the junction of pancreatic acini and ducts, these cells help maintain a balanced pH in the digestive system.
74. Interstitial Cells of Cajal
    • Function: Act as pacemakers in the gastrointestinal tract, coordinating smooth muscle contractions for peristalsis.
    • Special Feature: Found in the walls of the intestines, they help regulate the rhythm of muscle contractions during digestion.
75. Juxtaglomerular Apparatus Cells
    • Function: Involved in regulating kidney function, including blood pressure and filtration rate by releasing renin.
    • Special Feature: These specialized cells are located in the kidney and help monitor blood pressure and sodium concentration.
76. Podocyte Cells
    • Function: Form a filtration barrier in the kidneys, allowing small molecules to pass while preventing larger proteins from entering the urine.
    • Special Feature: These cells are located in the glomerulus and have foot-like processes that wrap around capillaries to filter blood.
77. Schwann Cells
    • Function: Produce the myelin sheath that surrounds axons in the peripheral nervous system, enabling fast transmission of nerve impulses.
    • Special Feature: These cells insulate axons to enhance the speed of electrical signal transmission along the nerve.
78. Pinealocytes
    • Function: Produce and secrete melatonin, a hormone that regulates sleep-wake cycles.
    • Special Feature: Located in the pineal gland, these cells are crucial for maintaining circadian rhythms.
79. Dust Cells (Alveolar Macrophages)
    • Function: Remove particles, pathogens, and debris from the alveoli in the lungs.
    • Special Feature: These specialized macrophages patrol the air sacs in the lungs, keeping the respiratory system free from infections and pollutants.
80. Thymic Epithelial Cells
    • Function: Support the development and maturation of T lymphocytes (T cells) in the thymus.
    • Special Feature: Provide a nurturing environment for immature T cells to develop into functional immune cells capable of fighting infections