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Princeton Brain, Spine, and Sports Medicine

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Anatomy & Function

The brain is arguably the most important organ in the human body. It controls and coordinates actions and reactions, allows us to think and feel, and enables us to have memories and feelings-all the things that make us human.

While the brain only weighs about three pounds, it is a highly complex organ made up of many parts. Years of scientific study have made it possible for scientists to identify the various areas of the brain and determine their specific functions. The following information provides a brief description of some of the major parts of the human brain.

The Cranium: Covering of the Brain

The brain is protected by a bony covering called the cranium. The cranium and the bones of the face make up the skull. Inside the cranium, the brain is surrounded by three layers of tissue called the meninges. The meninges include:

Pia mater: The layer closest to the surface of the brain

Arachnoid membrane: The middle layer of tissue

Dura mater: The outer-most layer

The Cerebrum: Front Part of the Brain

The largest part of the brain, located in the front, is called the cerebrum. The cerebrum is responsible for:

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Brain Anatomy | Princeton Brain, Spine, and Sports Medicine

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The brain is arguably the most important organ in the human body. It controls and coordinates actions and reactions, allows us to think and feel, and enables us to have memories and feelings-all the things that make us human. While the brain only weighs about three pounds, it is a highly complex organ made up of many parts.

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However, if you didn't have the cells that make up your heart, you wouldn't be able to pump blood throughout your entire body. If you bodies didn't get blood, our organs wouldn't be able to get the oxygen and nutrients they need to survive.  We wouldn't be able to get warm or cool off, fight infection, or get rid of our own waste product. Eventually we'll get too weak and die. Also, if you didn't have your immune system to fight off invaders, you wouldn't last more than a few days.

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Another important cell would be the reproductive cells. It's the first cell that defines a new person. The cell is call the "zygote" and it is a "totipotent" cell meaning it can turn into any cell in the human body. Every 12-24 hours the zygote divides until you have the tens and trillions of cell in a human body. However, this cell is only present in the very beginning of a human's life.

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It's hard to say which ones are the most important for the human body. Most people are tempted to say the brain cells are one of the most important cells in the human body since it coordinates all of the body’s life functions. The brain receives information from our 5 senses (sight, touch, taste, hear, and smell) and it assembles the messages in a way so it has meaning for us. Our brains controls our thoughts, memories and speech, movement of the arm and legs, and the function of many organs inside our bodies.

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The human body has over 200 different cell types. Each different types of cells has to carry out a specialized function, either alone, but usually by  forming a particular tissue. Then the different tissues combine and form a specific organs,and the organs are like a factory where every different types of cells has its own job.

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Author: Rachel Baxter, MSc * Reviewer: Francesca Salvador, MSc
Last reviewed: September 11, 2023
Reading time: 31 minutes

There are over 200 different cell types in the human body. Each type of cells is specialised to carry out a particular function, either solely, but usually by forming a particular tissue. Different tissues then combine and form specific organs, where the organ is like a factory where every type of cell has its own job.

Since every tissue has its own function that contributes to the multifunctionality of an organ, every type of cell is equally important. The most important types of cells are listed below.

Stem cells

Embryonic stem cells
Adult stem cells

Red blood cells

Erythrocytes

White blood cells

Granulocytes (neutrophils, eosinophils, basophils)
Agranulocytes (monocytes, lymphocytes)

Platelets

Fragments of megakaryocytes

Nerve cells

Neurons
Neuroglial cells

Muscle cells

Skeletal
Cardiac
Smooth

Cartillage cells

Chondrocytes

Bone cells

Osteoblasts
Osteoclasts
Osteocytes
Lining cells

Skin cells

Keratinocytes
Melanocytes
Merkel cells
Langerhans cells

Endothelial

Lining blood vessels

Epithelial cells

Lining body cavities

Fat cells

White adipocytes
Brown adipocytes

Sex cells

Spermatozoa
Ova

This article will discuss the histology of most important types of cells in the human organism.

Stem cells

Before a cell becomes specialised, it first starts out as a stem cell. The unique feature of stem cells is that they are pluripotent - they have the potential to become any type of cell in the body. These incredible cells are the ancestors of all cells in the body, from simple skin cells to complex neurons. Without these cells, we wouldn't be as complex or functional as human beings.

Not only this, these "magic" cells even have the power to replicate into healthy cells in order to speed up regeneration after certain pathological conditions. The process that allows stem cells to transform into any kind of cell is known as cell differentiation and is controlled by a combination of internal genetics and external factors such as chemicals and physical contact with other cells. Stem cells have the ability to divide and replicate themselves for long periods of time.

There are two types of stem cells, embryonic stem cells and adult stem cells. Embryonic stem cells are from embryos. Generally used in a research setting, embryonic stem cells are harvested from fertilised eggs. Adult (or somatic) stem cells are present throughout the human body [amongst other specialised tissue cells]. They exist in order to repair and maintain surrounding specialised tissues.

As these cells are unspecialised, stem cell anatomy is that of a simple cell. Stem cells have a cell membrane, surrounding the cytoplasm. The cytoplasm contains a nucleus, mitochondria, ribosomes, endoplasmic reticulum, golgi apparatus, lysosomes and centrioles. The nucleus contains DNA and RNA, which are expressed when differentiation occurs in the cell.

Red blood cells

Red bloodcells are known as erythrocytes, and are the most common type of blood cell. They are shaped like a biconcave disc (I.e. donut shaped). They have a diameter of around 6 to 8 µm and have an average thickness of 2 µm, being 2.5 µm thick at their thickest point and 1 µm thick at the center. Red blood cells are fairly flexible, allowing them to squeeze through thin blood capillaries.

The mainrole of red blood cells is to transport oxygen around the body using haemoglobin. However, they also help to control pH of the blood by forming an acid-base buffer maintaining the blood at a neutral pH of 7.35 to 7.45. They also release an enzyme called carbonic anhydrase, which causes water in the blood to carry carbon dioxide to the lungs, so that it can be expelled from the body.

Haemoglobin is a molecule in red blood cells that binds to oxygen, allowing it to be transported through the blood. Haemoglobin is comprised of a heme molecule and a globin molecule. Heme molecules are formed from succinyl-CoA and glycine. Four of these molecules together bind with iron forming a heme molecule. This combines with a globin polypeptide chain forming a haemoglobin chain (also named globulin chain). Four of these chains together create a haemoglobin molecule. There are four different types of haemoglobin chains; alpha, beta, gamma and delta. The most common combination is two alpha chains and two beta chains, which form a haemoglobin A molecule.

White blood cells

White blood cells, also known as leukocytes, are a vital component of the immune system. There are five different types, which fall under two main categories; granulocytes and agranulocytes. As suggested by their names, granulocytes contain granules in the cytoplasm as agranulocytes do not. Granulocytes include neutrophils, eosinophils and basophils. Agranulocytes include lymphocytes and monocytes.

Neutrophils

Neutrophils are the most common type of leukocyte, making up around 65% of all white blood cells. They are 12 to 14 µm in diameter, and contain a single nucleus. They contain few cell organelles and protein synthesis does not take place within them. Neutrophils originate in the bone marrow and circulate in the bloodstream for 6 to 10 hours, before entering the surrounding tissues. Once in the tissues, they destroy damaged cells and bacteria through phagocytosis, before self-destructing.

Eosinophils

Eosinophils are rare in the bloodstream. They are 12 to 17 µm in diameter and contain toxic proteins. Like neutrophils, they originate in the bone marrow and move into the bloodstream before entering loose connective tissue in the respiratory tract and intestines. Here they destroy antigen-antibody complexes using phagocytosis.

The cells release the specialised enzymes histaminase and arylsulfatase B which are involved in the inflammatory response. Eosinophils also play a role in destroying bacteria, viruses and parasites that invade the body.

Basophils

Basophils are the rarest form of white blood cell and are involved in the body's defense against parasites. They are 14 to 16 µm in diameter. They accumulate at infected areas, releasing histamines, serotonin and prostaglandins to increase blood flow which causes an inflammatory response.

Lymphocytes

Lymphocytes can be divided into two different types, B-cells and T-cells. Lymphocytes vary in size, with most being around 6 to 9 µm in diameter, and a tenth of them being 10 to 14 µm in diameter. The largest lymphocytes tend to be favored, and contain more cytoplasm, mitochondria and ribosomes than their smaller counterparts.

Both B-cells and T-cells are involved in the adaptive immune response, but have different roles. Both originate from haematopoietic stem cells in the bone marrow. However, T-cells mature in the thymus gland between the lungs and in front of the heart. The thymus gland atrophies into fat as children become adults yet can still stimulate the maturation of T-cells. B-cells develop into plasma cells and are involved in the synthesis of antibodies which attack foreign antigens. T-cells are involved in the destruction of bacteria, viruses and other damaging cells such as cancer cells.

The finaltype of white blood cells are the monocytes. These are as large as 20 µm in diameter. They have a large kidney bean shaped nucleus. Monocytes circulate in the bloodstream between one and three days before entering the tissues of the body where they become macrophages. Macrophages are large phagocytic cells that engulf and kill dead cells and bacterial cells.

Learning the types of cells is tricky business! Practice your tissue identifiction skills with our free histology slide worksheets, quizzes and labeling diagrams.

Platelets

Just like the white and red blood cells, platelets also form an important component of the blood. Technically platelets are fragments of cells rather than true cells, but are vital in the control of bleeding. They are fragments of large cells called megakaryocyteswhich are produced in the bone marrow. They have surface proteins which allow them to bind to one another, and to bind to damaged blood vessel walls. Platelets are recruited when bleeding occurs, initiating a process known as hemostasis. They plug the source of the bleeding, coagulating and sticking together to form a blood clot, together with a fibrous protein known as fibrin.

Megakaryocyte (histological slide)

Learn everything about the blood cells with the following study unit and quiz.

Nerve cells

Nerve cells,commonly known as neurons, transmit information throughout the body in the form of electrical signals or nerve impulses. Structurally, neurons have four specific regions; the cell body, dendrites, the axon and axon terminals. The cell body contains a nucleus and is responsible for synthesising neural proteins. The axon is long and thin, and protrudes from the cell body like a tail and can be myelinated or unmyelinated. Axons are responsible for conducting electrical impulses in the form of action potentials, away from the cell body.

Action potentials cause a change in voltage across the plasma membrane. Axons connect to other neurons via synapses, which are formed by small branches at the end of the axon called axon terminals. Impulses are received from other cells by dendrites, which are multiple branching structures protruding from the cell body.

Neurons can have multiple, two or one dendrite(s) which makes them multipolar, bipolar or unipolar respectively. They convert chemical signals from the synapse into small electrical impulses, and transmit them towards the cell body. Electrical disturbance in the dendrites is transmitted to a structure called the axon hillock at the base of the axon, and with enough voltage, generates an action potential which moves down the axon and continues its course.

Test your knowledge on the structure of the neuron with the quiz below!

Neuroglial cells

Neuroglial cells, more commonly known as glial cells or glia, are cells of the nervous system that are not involved in the conduction of nervous impulses. Glia are very common in the brain, outnumbering neurons at a ratio of 3 to 1. Glia are smaller than neurons, and do not have axons or dendrites. They have a variety of roles in the nervous system, they modulate synaptic action and rate of impulse propagation, they provide a scaffold for neural development, and aid recovery from neural injuries.

There are four types of glial cells in the central nervous system; astrocytes, oligodendrocytes, microglial cells, and ependymal cells. Astrocytes are found in the brain and spinal cord, and have a starlike appearance. They are involved in the maintenance of the chemical environment required for neuron signalling. Oligodendrocytes are responsible for forming a lipid-rich myelin sheath around axons, increasing the speed at which action potentials are conducted. Microglial cells are very small and are involved in the removal of debris from sites of injury. Ependymal cells line the ventricles and central canal of the brain to produce cerebrospinal fluid. In the peripheral nervous system, Schwann cells are responsible for the myelination of axons and satellite cells regulate the neural cell environment.

Muscle cells

There are 3 types of muscle cells, known as myocytes, in the human body. These types are skeletal, cardiac and smooth muscle. Skeletal and cardiac muscle cells are known as striated, due to the aligned arrangement of myosin and actin proteins within them. Actin and myosin allow muscle contraction by sliding past one another, as described by sliding filament theory. Actin and myosin are arranged more randomly in smooth muscle cells, creating a smooth rather than striated appearance.

Skeletal muscle cells

Skeletal muscle cells are attached to bones and tendons and can reach up to 30 cm in length, although they are usually 2 to 3 cm long. Skeletal muscle cells are responsible for voluntary movements. They are multinucleated and comprise a sarcolemma (cell membrane), sarcoplasm (cytoplasm), myofibrils (actin and myosin), sarcosomes (mitochondria) and a sarcoplasmic reticulum, which is like the smooth endoplasmic reticulum of other cells. They also contain two proteins called troponin and tropomyosin which regulate the interaction between actin and myosin during contraction. The basic units of striated muscle cells comprising actin and myosin are known as sarcomeres.

You've almost finished learning about the types of cells in the body - but what about the parts of a cell? Learn this topic easily and fuss-free using our handy diagams and cell quizzes!

Cardiac muscle cells

Cardiac muscle cells are also called cardiomyocytes which together make up the most important muscular tissue in the entire body, the tissue of the heart. Individually, they are about 0.02 mm wide and 0.1 mm long and linked together via gap junctions. The cells contract in unison creating the contractions of the heart. This is coordinated by nervous impulses which depolarises the cell membrane, spreading from cell to cell relatively quickly as the cells are very closely anchored via intercalated discs. Cardiomyocytes contain many sarcosomes to provide sufficient energy for contraction.

Smooth muscle cells

S​mooth muscle cells are responsible for involuntary contractions in hollow and visceral organs like the bladder and lungs, and the walls of blood vessels. They are responsible for peristalsis, whereby food is propelled through the digestive system via wavelike contractions.

They are 10 to 600 µm long spindle-shaped cells and have a central nucleus. Smooth muscle cells are arranged in sheets allowing them to contract simultaneously. As they are smaller than cardiomyocytes and skeletal myocytes, they contain fewer cell organelles, and do not contain sarcomeres.

Cartilage cells

Cartilage cells, also known as chondrocytes, make up cartilage, a firm tissue that is vital to the body's structure. Cartilage is found in joints between bones, in the ears and nose, in the airways as well as other locations. For example, cartilage can be found between the vertebrae in the spinal column.

Chondrocytes produce and maintain the extracellular matrix of cartilage, comprising collagen, proteoglycan and elastin fibers. They lack blood vessels meaning that cartilage is repaired slower than other tissues, and nutrients have to be absorbed by diffusion from the tissue surrounding the cartilage, known as the perichondrium. Articular cartilage (cartilage found in synovial joints) differs from other cartilages since it does not contain perichondrium.

Learn more and test your knowledge on the different types of cartilage with the following study unit and quiz!

Bone cells

There arefour types of bone cells in the body; osteoblasts, osteoclasts, osteocytes and lining cells.

Osteoclasts

Osteoclasts are large multinucleated cells that are involved in bone resorption. This is where the bone is broken down during the process of renewal. Osteoclasts break down bone by forming sealed compartments on its surface, and releasing enzymes and acids. After they complete the process, they die by apoptosis (programmed cell death).

Osteoblasts

Osteoblasts have the opposite function, they are involved in the generation of new bone. They are cuboidal in shape and have one central nucleus. They work by synthesising protein which forms the organic matrix of the bone. They are triggered to create new bone by hormones such as vitamin D and estrogen, and have specialised receptors on their surfaces which detect them.

Osteocytes

Osteocytes are cells that are found inside the bone. They have long branched structures protruding from them allowing cell to cell contact and access to the bone's surface. Osteocytes can sense mechanical strain being placed on the bone, and secrete growth factors which activate bone growth in response.

Lining cells

The finaltypeof bone cells are lining cells. These originate as osteoblasts before becoming flat in structure. As their name suggests, they line the surface of the bone and are responsible for the release of calcium from the bone into the bloodstream when it falls too low. Lining cells have receptors on their surfaces which are receptive to hormones and other chemicals that signify a need for bone growth and remodeling. They also work to protect the bone from chemicals in the blood which might be damaging to the bone's structure.

Go through these resources to solidify your knowledge about bone tissue:

Skin cells

There are many different types of cells in the epidermis (top layer) of the skin. The epidermis contains the following cell types:

Keratinocytes:These cells make up 95% of the epidermis and are sometimes known as basal cells, as they are found in the basal layer of the epidermis. Keratinocytes generate the protein keratin, but are also important in protecting the body by blocking toxins and pathogens, and preventing loss of heat and moisture. They also stimulate inflammation and secrete inhibitory cytokines. The outermost layer of epidermis is formed by keratinized epithelial cells which are responsible for forming the protective barrier. Hair and nails are examples of fully keratinized epithelial cells.

Melanocytes: The role of melanocytes in the skin is to produce the pigment melanin, which determines skin coloration.

Langerhans cells: These are dendritic cells involved in antigen processing when the skin becomes infected, they act as antigen-processing cells. They contain large organelles known as Birbeck granules, but the exact function of these is still unknown.

Merkel cells: These act as mechanosensory cells and are involved in touch reception (the ability to feel).

Othertypes of sensory cells are present within the skin, however are found in the deeper layers and known as cutaneous receptors.

Why not test your knowledge of the skin with some quiz questions?

Endothelial cells

Endothelial cells are the cells that form the lining of blood vessels. They are flat in structure, and are between 1 and 2 µm thick. They have a central nucleus, and are connected to one another via intercellular junctions. Endothelial cells are highly adaptable, being able to migrate and adjust their numbers and arrangements to accommodate the body's needs. This allows growth and repair of body tissues, as new blood vessel networks can easily form.

As well as healthy body tissues, cancer cells also rely on endothelial cells and blood vessels to survive As a result, a lot of research is focused on preventing the formation of blood vessels in cancerous tissues. Endothelial cells express different surface proteins, depending on whether they are forming veins or arteries.

Epithelial cells

Epithelial cells make up the linings of cavities in the body such as the lungs, small intestine and stomach. They are joined to one another forming sheets called epithelia, and are connected by tight junctions, adherens, desmosomes and gap junctions. Tight junctions are unique to epithelial cells and form the closest type of junction between any cell type in the body. They are supported by a basement membraneknown as a basal lamina, which covers a capillary bed. The nucleus of an epithelial cell is found close to the basal lamina, towards the bottom of the cell.

Epithelial cells are innervated with nerve endings, and can become sensory cells, detecting stimuli such as scent. Epithelial cells can also specialise to become secretory cells, that release mucous, hormones and enzymes into the body. These cells contain vesicles of hormones or enzymes ready to be released. Specialised secretory epithelial cells include goblet cells and paneth cells in the intestines, which secrete mucous and antibacterial proteins respectively.

Quiz yourself to reinforce what you have learned about the epithelial cells.

Fat cells

Fat cells, also referred to as adipocytes and lipocytes are the cells of the body that are specialised to store energy in the form of adipose tissue, or fat. There are two types of fat cell, white fat cells and brown fat cells. White fat cells, or unilocular cells, are vacuolar cells that contain a lipid droplet and cytoplasm. They have a nucleus which is flat and at the edge of the cell, rather than the centre. White fat cells vary in size, but on average they are around 0.1 mm in diameter. The fat inside white fat cells is mainly made up of triglycerides and cholesteryl ester, and is stored in semi-liquid form.

B​rown fat cells​, or multilocular cells, have multiple vacuoles and are shaped like polygons. They contain more cytoplasm that white fat cells, and fat droplets are scattered throughout them. The nucleus is not flattened but round, and is found randomly positioned towards the centre of the cell. The key role of brown fat is to generate heat energy, and therefore the cells contain many mitochondria, which give them their brownish coloration.

Sex cells

Sexual reproduction is the result of the fusion of two different types of sex cells called gametes. Male sex cells are commonly known as sperm cells, or spermatozoa, and female gametes are known as eggs or ova. When they fuse together, fertilization occurs and a zygote is formed.

Spermatozoa

Spermatozoa and ova are structurally very different from one another. Spermatozoa are smaller, being about 50 µm long, and have a head, a midpiece region and a long tail (flagellum) for propulsion and motility. The head contains an acrosome, which is a type of covering filled with enzymes that enable penetration of the female ovum during fertilisation. The head of the cell contains a nucleus that is densely packed with DNA, with little cytoplasm present. The midpiece region of the cell contains mitochondria which provide the energy required for locomotion.

Ova

Ova are very large compared to other cell bodies, being as large as 0.2 mm in diameter. They are round in shape and are produced in the ovaries during embryological development. The cell itself comprises a nucleus, cytoplasm, the zona pellucida and the corona radiata. The zona pellucida is a membrane that surrounds the cell membrane of the cell, and the corona radiata forms protective layers which surround the zona pellucida. During the process of fertilization, the spermatozoa binds with the ovum at the zona pellucida. After, the penetration of the spermatozoa and the release of its contents into the ovum can then occur (acrosome reaction).

Stem cells are pluripotent cells that have the potential to become any type of cell in the body through a process called differentiation. Stem cells have the ability to divide and replicate themselves for long periods of time. There are two types of stem cells, embryonic stem cells, and adult stem cells.

Red blood cells are known as erythrocytes and are the most common type of blood cell. They are shaped like a biconcave disc. Themainrole of red blood cells is to transport oxygen around the body using hemoglobin.

White blood cells, also known as leukocytes, are a vital component of the immune system. There are five different types, which fall under two main categories; granulocytes and agranulocytes. As suggested by their names, granulocytescontain granules in the cytoplasm as agranulocytesdo not. Granulocytes include neutrophils, eosinophils, and basophils. Agranulocytes include lymphocytes and monocytes.

Platelets are fragments of cells rather than true cells but are vital in the control of bleeding. They are fragments of large cells called megakaryocytes. They have surface proteins that allow them to bind to one another, and to bind to damaged blood vessel walls.

Nervecells,commonly known as neurons, transmit information throughout the body in the form of electrical signals or nerve impulses. Structurally, they have four specific regions; the cell body, dendrites, the axon and axon terminals. Neurons can have multiple, two or one dendrite(s) which makes them multipolar, bipolar or unipolarrespectively.

Neuroglialcells, more commonly known as glial cells or glia, are cells of the nervous system that modulate synaptic action and rate of impulse propagation, provide a scaffold for neural development, and aid recovery from neural injuries. Thereare four types of glial cells in the central nervous system; astrocytes, oligodendrocytes, microglial cells, and ependymal cells.

Thereare 3 types of muscle cells, known as myocytes, in the human body. These types are skeletal, cardiac and smooth muscle. Skeletal and cardiac muscle cells are known as striated, due to the aligned arrangement of myosin and actin proteins within them. Actin and myosin allow muscle contraction by sliding past one another, as described by sliding filament theory.

Cartilagecells, also known as chondrocytes, make up cartilage, a firm tissue that is vital to the body's structure. Chondrocytes produce and maintain the extracellular matrix of cartilage, comprising collagen, proteoglycan and elastin fibers.

Therearefour types of bone cells in the body; osteoblasts, osteoclasts, osteocytes, and lining cells. Osteoclasts are large multinucleated cells that are involved in bone resorption. Osteoblastshave the opposite function, they are involved in the generation of new bone. Osteocytes can sense mechanical strain being placed on the bone, and secrete growth factors that activate bone growth in response. Lining cells line the surface of the bone and are responsible for the release of calcium from the bone into the bloodstream when it falls too low.

There are many different types of cells in the epidermis (top layer) of the skin. The epidermis contains many types of cells, including keratinocytes, melanocytes, Langerhans cells, and Merkel cells.

Endothelial cells are the cells that form the lining of blood vessels and are connected to one another via intercellular junctions. Endothelial cells are highly adaptable, being able to migrate and adjust their numbers and arrangements to accommodate the body's needs.

Epithelial cells make up the linings of cavities in the body, forming sheets called epithelia. They are connected by tight junctions, adherens, desmosomes and gap junctions.

Fatcells, also referred to as adipocytes and lipocytes, are the cells of the body that are specialized to store energy in the form of adipose tissue, or fat. There are two types of fat cells, white fat cells and brown fat cells.

Sexual reproduction is the result of the fusion of two different types of sex cells called gametes. Male sex cells are commonly known as sperm cells or spermatozoa, and female gametes are known as eggs or ova. When they fuse together, fertilization occurs and a zygote is formed.

References:

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Excitable Tissues (Smooth Muscle).Queen Margaret University (accessed 2nd August 2016)

H. Lodish, A. Berk, S. L. Zipursky, et al.: Molecular Cell Biology, 4th Edition, W. H. Freeman (2000)

J. McGeachie: Endothelial Cells. The University of Western Australia School of Anatomy and Human Biology (accessed 2nd August 2016)

J. P. Whickson: What is the Structure of Stem Cells? Cuteness (accessed 3rd August 2016)

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Keratinocytes. Keratinocyte transfection (accessed 2nd August 2016)

M. Cichorek, M. Wachulska, A. Stasiewicz, et al.: Skin Melanocytes. biology and development. Advances in Dermatology and Allergology (2013), volume 30, issue 1, p. 30-41

M. Harms, P. Seale: Brown and beige fat: development, function andtherapeutic potential. Nature Medicine (2013), volume 19, p. 1252-1263

M. J. Oursler, T. Bellido: Bone Cells. ASBMR Bone Curriculum (accessed 2nd August 2016)

M. P. Gaidhu, R. B. Ceddia: The Role of Adenosine Monophosphate Kinase in Remodeling the White Adipose Tissue Metabolism. Exercise and Sports Science Reviews (2011), volume 39, issue 2, p. 102-108

Overview of Epithelial Cells. Davidson College Biology Department(accessed 2nd August 2016)

R. Bailey: Sex Cells. About Education(accessed 2nd August 2016)

Skeletal Muscle Structure.University of California(accessed 1st August 2016)

S. Maksimovic, M. Nakatani, Y. Baba, et al.: Epidermal Merkel cells are mechanosensory cells that tune mammalian touch receptors. Nature (2014), volume 509, issue 7502, p. 617-621

What are Adult Stem Cells? National Institute of Health(accessed 3rd August 2016)

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This article describes the characteristics, function and location of the various types of cells in the human body. Learn this topic now at Kenhub!

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Which human cell is the most important?

Question Date: 2014-08-26

Answer 1:

It's hard to say which type of human cell is most important because we need most all of them to survive. It is sort of similar to asking which part of a car is most important. Most people would say the engine, but without the bolts securing the engine, the engine wouldn't be useful. Similarly, for the human body, it is tempting to say the brain cells are most important because they coordinate all of the body's life functions. However, without the cells that make up your heart, you wouldn't be able to pump blood throughout your body. Also, without your immune cells to defend against invaders, you wouldn't last more than a few days. So for a full grown human, there are certainly cells that are more important to keeping a human alive, but ultimately they all play an important part.

Though, if you talk about the entire life of a human, the most important cell would be the fertilized egg cell or "zygote". This is the first cell that that defines a new person, different than their mother or father. The zygote is a "totipotent" cell meaning it can turn into any cell in the human body. The zygote divides every 12-24 hours until you have the tens of trillions of cells in a mature human! This cell is only present in the very beginning of a human's life though.

Answer 2:

Every cell in the human body is very important. Although each individual cell can not do the work of all trillion cells we have, they are important. We have neurons which are cells that transport messages to and from the brain. We have optical cells in our eyes that take in light to see our surroundings. We have cells in our ears that support the hairs that detect sounds. Our skin cells protect us from diseases and other harm.

If you forced me to chose a type of cell that is most important, I would pick our stem cells. These cells live for as long as we are alive. This is different from regular cells that die and are replaced by new ones. Stem cells can make ANY cell in your body. It can be a cell in your tongue, a bone cell, a cell in your eye, or a skin cell. Since this type of cell can make any other type of cell, and lives so long, I'd say it is the most important. That is my opinion - I hope you get other answers to see if we agree or disagree (which is a part of science!).

Answer 3:

There is no way to answer this. Each human cell has its use. Many of those uses are needed for the human to live. If forced to pick one, however, it would be the stem-cells: the cells that create all other cells.

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Which human cell is the most important? Question Date: 2014-08-26 Answer 1: It's hard to say which type of human cell is most important because we need most all of them to survive. It is sort of similar to asking which part of a car is most important.

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Some of the most important cells in the human bodies are the brain cell,the reproductive cells, the cells that make up the heart and the immune system. Although they may be some of the most important, we still need all the other cells in our body to function properly as a human.