Name: human skeleton: bones, cells, and disease
Uploaded: 2019-03-11T09:21:29.000Z
Duration: 1 min 2 s
Channel: JoVE

K12 Standards

Next Generation Science Standards

High School

Life Science

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

HS-LS1-2

What is the Skeletal System?

- [Instructora] El esqueleto
humano está compuesto de

huesos

que no solo se unen para
proporcionar una estructura

rígida,

dándole forma al cuerpo,
sino que también permiten

movimiento,

ya que están unidos a
músculos a través de tendones.

Una de las divisiones principales,

el esqueleto axial,

está dispuesto alrededor
del eje central del cuerpo.

Mientra que hay un número
de huesos en esta sección

de la parte superior del
cuerpo, incluyendo los osículos

del oído medio,

la mayoría protegen órganos
vitales de algún daño.

Por ejemplo, el cráneo rodea el cerebro,

y la columna vertebral
se arquea alrededor de

la médula espinal,

protegiendo el sistema nervioso central.

Otros órganos, como el
corazón y los pulmones,

están protegidos por el
esternón y la caja torácica.

La otra división, el
esqueleto apendicular,

consiste en huesos que
soportan y mueven las

extremidades,

las manos y los brazos, así
como los pies y las piernas,

y la cintura pélvica y escapular.

Kling, Juliana M., Bart L. Clarke y Nicole P. Sandhu. "Prevención, detección y tratamiento de la osteoporosis: una revisión". Journal of Women's Health 23, no. 7 (1 de julio de 2014): 563–72. [<a href="https://doi.org/10.1089/jwh.2013.4611" target="__blank">Fuente</a>]

Akkawi, Ibrahim y Hassan Zmerly. "Osteoporosis: conceptos actuales". Articulaciones 6, n.º 2 (14 de junio de 2018): 122–27. [<a href="https://doi.org/10.1055/s-0038-1660790" target="__blank">Fuente</a>]

¿qué es el sistema esquelético?

<h4>Descripción general</h4> El esqueleto humano adulto está formado por 206 huesos que están conectados mediante cartílagos, tendones y ligamentos. El esqueleto proporciona un marco rígido para el cuerpo humano, protege los órganos internos y permite el movimiento y la locomoción. El sistema esquelético humano está formado por los esqueletos axial y apendicular. El tejido óseo se construye y mastica continuamente mediante células óseas especializadas que son esenciales para la salud general. Las células óseas desreguladas y los niveles incorrectos de compuestos químicos en la sangre provocan enfermedades óseas. <h4>Esqueleto axial</h4> El esqueleto axial está formado por 80 huesos y se divide en tres regiones: el cráneo, la columna vertebral y la caja torácica. El cráneo, está formado por ocho huesos que encierran el cerebro, aunque la parte inferior está formada por 14 huesos. La columna vertebral está formada por 33 vértebras: siete cervicales, 12 torácicas, cinco lumbares, cinco sacras fusionadas y cuatro coccígeas fusionadas. La caja torácica añade estabilidad a la columna vertebral y también protege los pulmones y el corazón. Está formada de 12 pares de costillas, que se unen a la vértebra torácica a través de la articulación costovertebral. La porción anterior de la caja torácica se une al esternón,el hueso plano en el centro de la parte frontal del tórax, a través de los cartílagos costales. Las primeras siete costillas de cada lado se conocen como costillas verdaderas, ya que sus cartílagos se unen directamente al esternón. Las costillas ocho a 12 se llaman costillas falsas porque no se unen directamente al esternón. Sin embargo, las costillas ocho a diez se unen al esternón a través de los cartílagos costales de las costillas superiores. Por el contrario, las costillas 11 y 12 se denominan costillas flotantes, ya que sólo están unidas a la columna vertebral por la parte posterior, pero no tienen conexión alguna con el esternón. <h4>Esqueleto apendicular</h4> El sistema esquelético apendicular está formado por los 126 huesos de las extremidades y las cinturas, ya que están adheridos al esqueleto axial. El sistema esquelético apendicular está formado por varios tipos diferentes de huesos. <h4>Tejido óseo y células</h4> Al hueso se le conoce como tejido óseo. Las células del tejido óseo están dispersas en la matriz, la sustancia que proporciona fuerza y dureza a los huesos. La matriz está formada por componentes orgánicos, principalmente colágeno, y componentes inorgánicos que consisten en sales minerales cristalizadas como fosfato de calcio, hidróxido de calcio y fluoruro de magnesio. Hay tres tipos principales de células óseas,osteoblastos, osteoclastos y osteocitos. Los osteoblastos y los osteoclastos tienen funciones opuestas. Los osteoblastos construyen la matriz ósea, aunque los osteoclastos la mastican. Ambas funciones continúan durante toda la vida y ambas son esenciales para una buena salud. La formación de huesos es importante para mantenerlos fuertes. Masticar hueso permite mantener los niveles de calcio en el torrente sanguíneo (que es vital para la salud de otros órganos, como el corazón). Los osteocitos son células que han madurado a partir de osteoblastos y ahora están rodeadas de matriz. Los osteocitos se comunican con la sangre a través de canales microscópicos en el hueso, detectando los niveles de calcio y otros minerales en la sangre. Luego controlan las funciones de los osteoblastos y osteoclastos secretando sustancias que afectan la actividad de estas células. <h4>Enfermedades óseas</h4> Muchas enfermedades del sistema esquelético tienen una característica común: huesos débiles debido al bajo contenido de minerales. La osteoporosis, por ejemplo, se caracteriza por una disminución de la densidad mineral ósea. Ocurre con mayor frecuencia en mujeres posmenopáusicas, pero también puede ocurrir en hombres y mujeres premenopáusicas. En esta enfermedad, hay más actividad de osteoclastos que de osteoblastos. Los pacientes con osteoporosis tienen un riesgo mucho mayor de sufrir fracturas, especialmente de columna vertebral, cadera y muñeca. Otra enfermedad ósea muy extendida es la osteodistrofia renal. Esta enfermedad es parte de una afección más amplia conocida como trastorno mineral y óseo en la enfermedad renal crónica. Los riñones realizan muchas funciones, incluida la regulación del calcio, el fósforo y la vitamina D, todas ellas fundamentales para la salud ósea. Cuando los riñones no funcionan correctamente, como en la enfermedad renal diabética, los huesos pueden debilitarse y causar dolor, y las articulaciones también pueden volverse dolorosas.

¿Qué es el sistema esquelético?

Visión general

El esqueleto humano adulto consta de 206 huesos que están conectados a través de cartílagos, tendones y ligamentos. El esqueleto proporciona una ...

Education

Educación

JoVE Core

Biology

Biología

Human Biology

Biología Humana

Musculoskeletal System

Sistema musculoesquelético

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

human skeleton: bones, cells, and disease

The human skeleton is a living framework made of 206 bones in adults. Bones connect with cartilage, tendons, and ligaments. This system gives the body support, protects organs, and helps with movement and locomotion.

The skeleton has two main parts: the axial skeleton and the appendicular skeleton. The axial skeleton has 80 bones and includes the skull, the vertebral column, and the rib cage. The cranium, or upper skull, has eight bones that enclose the brain, while the lower part of the skull has 14 bones. The vertebral column has 33 vertebrae. These include seven cervical, 12 thoracic, five lumbar, five fused sacral, and four fused coccygeal vertebrae.

The rib cage adds stability to the vertebral column and protects the lungs and heart. It has 12 pairs of ribs that attach to the thoracic vertebrae at the costovertebral joint. The front of the rib cage connects to the sternum, the flat bone in the center of the chest, through costal cartilages. The first seven ribs are true ribs because their cartilages attach directly to the sternum. Ribs eight through 12 are false ribs. Ribs eight through 10 connect to the sternum through the cartilages of the ribs above them, while ribs 11 and 12 are floating ribs because they do not connect to the sternum at all.

The appendicular skeleton has 126 bones. It includes the bones of the limbs and the girdles that attach them to the axial skeleton. Bone tissue is also called osseous tissue. Its cells sit in a matrix, which is the material that gives bone strength and hardness. The matrix contains organic material, mainly collagen, and inorganic mineral salts such as calcium phosphate, calcium hydroxide, and magnesium fluoride.

Bone cells have different jobs. Osteoblasts build bone matrix, while osteoclasts break it down. Both actions continue throughout life and are important for health. Building bone helps keep bones strong. Breaking down bone helps maintain calcium levels in the bloodstream, which is important for organs such as the heart. Osteocytes are mature bone cells that come from osteoblasts. They sit inside the matrix and communicate with the blood through tiny channels in bone. They sense calcium and other mineral levels and help control osteoblast and osteoclast activity by releasing substances that affect these cells.

Problems in bone cell balance or mineral levels can lead to bone disease. Osteoporosis is a common example. It is marked by low bone mineral density and more osteoclast activity than osteoblast activity. It occurs most often in postmenopausal women, but it can also occur in men and premenopausal women. People with osteoporosis have a much higher risk of fractures, especially in the spine, hip, and wrist.

Renal osteodystrophy is another widespread bone disease. It is part of mineral and bone disorder in chronic kidney disease. The kidneys help regulate calcium, phosphorus, and vitamin D, and these are all needed for bone health. When the kidneys do not work properly, such as in diabetic kidney disease, bones may become weak and painful, and the joints may hurt as well.

Human Skeleton: Bones, Cells, and Disease

what is the skeletal system?

The human skeleton is a living framework made of 206 bones in adults. Bones connect with cartilage, tendons, and ligaments. This system gives the body support, protects organs, and helps with movement and locomotion. The skeleton has two main parts: the axial skeleton and the appendicular skeleton. The axial skeleton has 80 bones and includes the skull, the vertebral column, and the rib cage. The cranium, or upper skull, has eight bones that enclose the brain, while the lower part of the skull...

bone structure

Inside a Long Bone

Inside a long bone, osseous tissue is organized into two main types: cortical bone and cancellous bone. A femur is a clear example of this structure. The bone also includes outer coverings and inner spaces that support growth, repair, and blood cell production. Cortical bone, also called compact bone, forms the dense outer layer along the diaphysis, or shaft. It is covered by the periosteum, a membrane with connective tissue, capillaries, and nerves. Beneath the cortical layer is the medullary...

joints

Types of Joints in the Human Body

Joints are the places where adjacent bones connect. They are also called articulations or articular surfaces. Joints help the body move and stay stable. Joints can be classified by structure or by function. Structural classification depends on the material that forms the joint and whether there is a space between the bones. By structure, joints are fibrous, cartilaginous, or synovial. Fibrous joints are connected by fibrous tissue and have no cavity between the bones. Because of this, they do...

bone remodeling

How Hormones Control Bone Turnover

Bone turnover is a continuous process in which old bone is broken down and new bone is built. Osteoclasts carry out bone resorption, and osteoblasts carry out bone formation. In adults, this balanced cycle helps maintain bone mass and calcium homeostasis. Mechanical stress can also stimulate turnover as part of normal maintenance and repair. Parathyroid hormone, or PTH, helps control blood calcium levels by increasing bone resorption when calcium is low. It is released from the parathyroid...

skeletal muscle anatomy

Muscle Fibers, Tendons, and Contraction

Skeletal muscle moves the body by pulling on bones through tendons. Tendons are the connective tissue that attaches skeletal muscle to bones. When skeletal muscles contract, they create voluntary movement. Skeletal muscle is wrapped in layers of connective tissue. The outer layer is the epimysium, which helps protect the muscle. Beneath it, the perimysium surrounds and groups fasciculi, which are bundles of skeletal muscle cells called myocytes. These cells are also called skeletal muscle...

classification of skeletal muscle fibers

Skeletal Muscle Fiber Speed and Energy

Skeletal muscle fibers can be grouped by how fast they contract and how they make ATP, the energy cells use for movement. These differences also shape their physical features. Most human muscles contain all three fiber types, but in different amounts. Slow oxidative fibers, also called slow-twitch fibers, appear red because they have many capillaries and high levels of myoglobin, an oxygen-storing protein. They also contain more mitochondria, which make ATP through oxidative phosphorylation,...

muscle contraction

Nerve Signals That Trigger Muscle Contraction

Nerve signals trigger muscle contraction in both skeletal and smooth muscle, but the two muscle types use different control systems. In skeletal muscle, the signal begins at the motor end plate, which is the synapse between a motor neuron and a muscle fiber. In smooth muscle, contraction is controlled by the autonomic nervous system and happens without conscious control. In skeletal muscle, motor nerve terminals release acetylcholine. This neurotransmitter binds to receptors on the sarcolemma,...

cross-bridge cycle

Calcium Control in Muscle Contraction

Calcium control in muscle contraction depends on ATP, motor neurons, and the sliding action of actin and myosin. As a muscle contracts, the thin and thick filaments overlap more, and the sarcomere, which is the contractile unit of the muscle, becomes shorter. This process uses energy from ATP and happens in a repeating cycle at the molecular level. Myosin drives the movement of actin through a cross-bridge cycle. When ATP attached to the myosin head is hydrolyzed to ADP, myosin shifts into a...

motor units

How Motor Units Control Muscle Movement

Motor units control skeletal muscle movement. A motor unit includes one efferent motor neuron, which carries signals away from the central nervous system, and all of the muscle fibers it innervates. A single motor neuron can connect with multiple muscle fibers, but each muscle fiber is innervated by only one motor neuron. Lower motor neurons are the efferent neurons that control skeletal muscle, the most abundant type of muscle in the body. Their cell bodies are found in the spinal cord or...

the spinal cord

Spinal Cord Structure and Dermatomes

The spinal cord is the main nerve pathway of the central nervous system. It carries sensory signals from the body to the brain and motor signals from the brain to the body. It begins at the foramen magnum, the opening at the base of the skull, and extends to the level of the first or second lumbar vertebra. In cross-section, the spinal cord is cylindrical and contains both gray matter and white matter. The central canal lies in the middle and is a remnant of the lumen of the primitive neural...

nociception

Pain Signaling and Inflammation

Pain signaling begins when the body detects a harmful stimulus. Sharp objects, open flames, and corrosive chemicals can trigger this response. Sensory receptors called nociceptors, which sit on nerve endings, detect these noxious stimuli and use ion channels to turn them into electrical signals. Those electrical signals travel through sensory neurons to the brain, where they are experienced as pain. This warning system helps an organism avoid damage and stay safe. Pain is therefore an...

key terms and concepts

Explore the human skeleton, including axial and appendicular bones, bone cells, and common bone diseases like osteoporosis and renal osteodystrophy.

Human Skeleton: Bones, Cells, and Disease | JoVE K12

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New York State Science Learning Standards

Structure and Function

HS-LS1-2.

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HS-LS1-3

Human Skeleton: Bones, Cells, and Disease

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