33.2 Animal Primary Tissues
4 min read•june 14, 2024
Animal tissues form the building blocks of complex body systems. Epithelial, connective, muscle, and nervous tissues each have unique structures and functions that work together to maintain life.
From the closely packed cells of to the specialized components of nervous tissue, these primary tissues enable animals to move, sense their environment, and maintain internal balance. Understanding their characteristics is key to grasping animal physiology.
Animal Primary Tissues
Characteristics of epithelial tissues
Top images from around the web for Characteristics of epithelial tissues
Epithelial Tissues | Biology for Majors II View original
Is this image relevant?
4.1 Types of Tissues – Douglas College Human Anatomy and Physiology I (1st ed.) View original
Is this image relevant?
Epithelial Tissue | Anatomy and Physiology I View original
Is this image relevant?
Epithelial Tissues | Biology for Majors II View original
Is this image relevant?
4.1 Types of Tissues – Douglas College Human Anatomy and Physiology I (1st ed.) View original
Is this image relevant?
1 of 3
Top images from around the web for Characteristics of epithelial tissues
Epithelial Tissues | Biology for Majors II View original
Is this image relevant?
4.1 Types of Tissues – Douglas College Human Anatomy and Physiology I (1st ed.) View original
Is this image relevant?
Epithelial Tissue | Anatomy and Physiology I View original
Is this image relevant?
Epithelial Tissues | Biology for Majors II View original
Is this image relevant?
4.1 Types of Tissues – Douglas College Human Anatomy and Physiology I (1st ed.) View original
Is this image relevant?
1 of 3
- Cells are closely packed with little intercellular space minimizing the risk of pathogen invasion and fluid loss
- Cells are polarized, with apical and basal surfaces allowing for specialized functions such as secretion and absorption
- Cells rest on a providing structural support and separating the epithelium from underlying tissues
- Avascular, receiving nutrients from underlying connective tissue via diffusion (oxygen, glucose)
- Innervated, but lacks nerve fibers within the tissue enabling sensation without direct nervous control
Types of connective tissues
- has an abundant and loosely organized
- are the main cell type producing , , and other components
- stores energy in the form of lipids (fat cells)
- provides support and cushioning between organs (skin, mucous membranes)
- forms a supportive framework in lymphatic organs (lymph nodes, spleen)
- Dense connective tissue has an rich in collagen fibers
- Fibroblasts are the main cell type producing and maintaining the collagen-rich matrix
- connect muscles to bones and withstand tension (Achilles tendon)
- connect bones to bones and provide stability (anterior cruciate ligament)
- is the thick, inner layer of the skin providing strength and elasticity
- Specialized have unique structures and functions
- is firm and flexible, with embedded in a matrix rich in collagen and
- covers joint surfaces and provides shock absorption (knee, elbow)
- maintains shape and allows flexibility (external ear, epiglottis)
- withstands compression and tension (intervertebral discs, pubic symphysis)
- Bone is hard and mineralized, with embedded in a matrix of collagen and calcium phosphate
- forms the dense outer layer of bones providing strength (femur, humerus)
- forms the porous inner layer of bones reducing weight (vertebrae, pelvis)
- Blood is a liquid connective tissue with plasma and various blood cells
- (red blood cells) transport oxygen and carbon dioxide
- (white blood cells) defend against pathogens and foreign substances
- (thrombocytes) initiate blood clotting and promote wound healing
- is firm and flexible, with embedded in a matrix rich in collagen and
Structure of muscle tissues
- has spindle-shaped cells with a single nucleus
- Lack and striations resulting in slow, sustained contractions
- and connect cells allowing for coordinated contractions
- Involuntary contraction is controlled by the autonomic nervous system
- Found in walls of hollow organs (intestines, uterus) and blood vessels
- has long, cylindrical cells with multiple nuclei
- Sarcomeres and striations present enabling rapid, powerful contractions
- Cells are bundled into surrounded by connective tissue (, , )
- Voluntary contraction is controlled by the somatic nervous system
- Attached to bones via tendons, enabling movement (biceps, quadriceps)
- has branched cells with a single nucleus
- Sarcomeres and striations present allowing for strong, rhythmic contractions
- connect cells permitting the spread of electrical impulses
- Involuntary, rhythmic contraction is controlled by the cardiac conduction system
- Found only in the heart, pumping blood throughout the body ()
Components of nervous tissue
- are the primary functional units of the nervous system
- Cell body () contains the nucleus and organelles for protein synthesis and energy production
- are branched extensions that receive signals from other neurons (postsynaptic)
- is a long, thin extension that conducts electrical impulses away from the cell body (presynaptic)
- Transmit electrical and chemical signals via and
- Process and integrate information from multiple inputs to generate appropriate outputs
- provide support, protection, and maintenance for neurons
- regulate the chemical environment, provide nutrients, and maintain the blood-brain barrier
- produce around axons in the central nervous system (brain, spinal cord)
- produce myelin sheath around axons in the peripheral nervous system (nerves)
- are the resident immune cells of the nervous system, removing debris and protecting against pathogens
- Myelin sheath is an insulating layer of lipids and proteins around axons
- Produced by oligodendrocytes (CNS) and Schwann cells (PNS)
- Increases the speed of impulse conduction by enabling ()
- Damage to myelin can lead to impaired nervous function (multiple sclerosis, Guillain-Barré syndrome)
- Nervous tissue plays critical roles in sensing, processing, and responding to stimuli
- Sensory input: receives and processes information from sensory receptors (touch, vision, hearing)
- Integration: interprets and analyzes sensory information in the brain and spinal cord
- Motor output: initiates and controls muscle contractions (skeletal, cardiac, smooth) and glandular secretions
Tissue Development and Maintenance
- is the study of tissue structure and function at the microscopic level
- is the process by which cells become specialized for specific functions
- is maintained through the coordinated functions of various tissues
- allows for the repair and replacement of damaged tissues
- The extracellular matrix provides structural support and influences cell behavior
Key Terms to Review (80)
Action potentials: Action potentials are rapid, temporary changes in the electrical membrane potential of a neuron or muscle cell that occur when it becomes depolarized and then repolarizes. They are crucial for the transmission of signals along neurons and play a key role in processes like muscle contraction and sensory perception, acting as the primary means of communication in the nervous system.
Adipose tissue: Adipose tissue is a type of connective tissue primarily responsible for storing energy in the form of fat, providing insulation and cushioning for organs. This tissue plays a crucial role in metabolism and energy balance, as it interacts closely with various hormones and body processes to regulate energy homeostasis and thermoregulation.
Areolar tissue: Areolar tissue is a loose connective tissue that acts as a binding framework for various organs and structures in the body. It is composed of a gel-like matrix filled with collagen and elastin fibers, providing strength and flexibility, while also housing various cell types, including fibroblasts, macrophages, and mast cells. This tissue plays a crucial role in providing support and nourishment to other tissues, facilitating the exchange of nutrients and waste products.
Astrocytes: Astrocytes are a type of glial cell in the central nervous system that provide structural and metabolic support to neurons. They play crucial roles in maintaining the blood-brain barrier, regulating blood flow, and modulating synaptic activity, which are all essential for proper brain function and homeostasis.
Axon: An axon is a long, slender projection of a neuron that conducts electrical impulses away from the cell body toward other neurons or muscles. This structure is crucial for the transmission of signals in the nervous system, as it allows for communication over long distances within the body. The axon can be covered by a myelin sheath, which enhances the speed of impulse conduction through a process called saltatory conduction.
Basement membrane: The basement membrane is a thin, fibrous layer of extracellular matrix that separates epithelial tissue from underlying connective tissue. It provides structural support and anchoring for epithelial cells while also playing a crucial role in filtration, cellular signaling, and tissue repair.
Bipolar neurons: Bipolar neurons are specialized sensory neurons with one axon and one dendrite extending from opposite ends of the cell body. They are involved in transmitting sensory information such as taste and smell to the central nervous system.
Canaliculi: Canaliculi are microscopic channels found within bone tissue. They facilitate communication and nutrient exchange between osteocytes.
Cardiac muscle: Cardiac muscle is a specialized type of striated muscle found only in the heart, responsible for pumping blood throughout the body. This unique muscle type features intercalated discs that connect individual cardiac cells, allowing for coordinated contractions essential for effective heart function. Its involuntary nature ensures that it operates without conscious control, making it crucial for sustaining life.
Cardiac muscle tissue: Cardiac muscle tissue is a specialized type of muscle found only in the heart. It is responsible for the rhythmic contractions that pump blood throughout the body.
Cartilage: Cartilage is a flexible connective tissue found in various parts of the body, including joints, ear, nose, and respiratory tract. It provides structure and cushioning to these areas without being as hard or rigid as bone.
Cartilage: Cartilage is a flexible connective tissue found in various parts of the body, including joints, ribcage, ear, nose, and intervertebral discs. It provides support and cushioning, allowing for smooth movement of joints and structural integrity in areas that require both strength and flexibility. The absence of blood vessels in cartilage makes it unique, as nutrients are supplied through diffusion.
Chondrocytes: Chondrocytes are the cells found in cartilage tissue responsible for maintaining the cartilaginous matrix. They play a crucial role in cartilage formation, growth, and repair.
Chondrocytes: Chondrocytes are specialized cells found in cartilage tissue that are responsible for the maintenance and synthesis of cartilage matrix components, including collagen and proteoglycans. These cells play a crucial role in the growth and repair of cartilage, which is essential for providing support and flexibility to joints and other structures in the body. Chondrocytes are embedded within the extracellular matrix they produce, which allows them to maintain the structural integrity of cartilage.
Collagen: Collagen is a structural protein that forms a key component of connective tissues in animals, providing strength and elasticity. It plays a vital role in maintaining the integrity of various tissues, including skin, bones, cartilage, and tendons, linking it to essential functions in cellular activities and tissue structure.
Columnar epithelial: Columnar epithelial cells are elongated cells found lining various organs, including the digestive tract and respiratory system. They play roles in secretion, absorption, and protection.
Compact bone: Compact bone is a dense and strong type of osseous tissue that forms the outer layer of bones, providing structural support and protection. It consists of tightly packed osteons, or Haversian systems, which contain blood vessels and nerves, allowing for nutrient exchange and communication within the bone. This type of bone is crucial for the overall strength and rigidity of the skeletal system.
Connective tissues: Connective tissues are a group of tissues that support, connect, or separate different types of tissues and organs in the body. They are characterized by an extracellular matrix that is rich in protein fibers.
Cuboidal epithelial: Cuboidal epithelial cells are a type of epithelial tissue characterized by their cube-like shape and central, spherical nuclei. They are typically found in glands, ducts, and portions of the kidney tubules where they function in secretion and absorption.
Dendrites: Dendrites are branched projections of a neuron that receive electrical signals from other neurons. They play a crucial role in the communication between neurons, allowing them to process and transmit information effectively. The structure of dendrites increases the surface area available for synaptic connections, facilitating the integration of signals from various sources.
Dermis: The dermis is the thick layer of skin located beneath the epidermis, consisting of connective tissue, blood vessels, and various cells that support and nourish the skin. This layer plays a crucial role in maintaining skin integrity, providing strength and elasticity through collagen and elastin fibers, and housing important structures like hair follicles, sweat glands, and sensory receptors.
Desmosomes: Desmosomes are specialized intercellular junctions that provide strong adhesion between cells, particularly in tissues subjected to mechanical stress. They are composed of cadherin proteins and anchor to intermediate filaments within the cell.
Desmosomes: Desmosomes are specialized cell structures that provide strong adhesion between adjacent cells, ensuring the integrity and stability of tissues under mechanical stress. They consist of protein complexes that anchor the cytoskeleton of one cell to that of another, forming a resilient connection that is crucial in tissues like the skin and heart, where cells experience significant tension and strain.
Differentiation: Differentiation is the biological process by which unspecialized cells become specialized into distinct cell types with specific functions. This process is crucial for the development and organization of multicellular organisms, allowing for the formation of various tissues and systems that carry out specific tasks essential for survival.
Elastic cartilage: Elastic cartilage is a type of connective tissue that provides both strength and flexibility due to its unique composition, which includes a dense network of elastic fibers. This specialized tissue supports structures that require resilience and shape retention, like the external ear and the epiglottis. Elastic cartilage is crucial for maintaining the integrity of these structures while allowing them to bend and return to their original form.
Elastin: Elastin is a key protein in the connective tissue that provides elasticity and resilience to various structures in the body, allowing them to return to their original shape after being stretched or deformed. This protein plays a crucial role in maintaining the structural integrity and functionality of organs and tissues, such as skin, blood vessels, and lungs, ensuring they can withstand mechanical stress.
Endomysium: The endomysium is a delicate connective tissue layer that surrounds individual muscle fibers (muscle cells) within skeletal muscle tissue. This thin layer plays a vital role in supporting and protecting muscle fibers, as well as facilitating the exchange of nutrients and waste products between the fibers and blood vessels. It also provides a pathway for nerves and blood vessels to reach each muscle fiber, ensuring proper function and coordination of muscle contractions.
Epimysium: The epimysium is a dense layer of connective tissue that surrounds an entire muscle, providing structural support and protection. It plays a vital role in the organization of muscle fibers and helps to transmit the forces generated by muscle contractions to the tendons, which ultimately attach to bones. Additionally, the epimysium contains blood vessels and nerves that supply the muscle tissue.
Epithelial tissues: Epithelial tissues are layers of cells that cover body surfaces and line internal organs and cavities. They serve as protective barriers, aid in absorption, secretion, and sensation.
Epithelial tissues: Epithelial tissues are a type of primary tissue that forms the protective outer layer of the body and lines internal organs and cavities. These tissues serve critical functions such as protection, absorption, secretion, and sensation, helping to maintain the integrity and functionality of various body systems. Epithelial tissues are characterized by closely packed cells with minimal extracellular matrix, and they can be classified based on cell shape and the number of cell layers.
Erythrocytes: Erythrocytes, commonly known as red blood cells, are specialized cells in the bloodstream responsible for transporting oxygen from the lungs to body tissues and carbon dioxide from the tissues back to the lungs. These biconcave, disc-shaped cells lack a nucleus and organelles, allowing for more space to carry hemoglobin, the protein that binds oxygen. Their unique structure and function make them essential components of blood and play a critical role in maintaining cellular respiration and overall homeostasis.
Extracellular matrix: The extracellular matrix (ECM) is a complex network of proteins and polysaccharides secreted by cells into their external environment. It provides structural and biochemical support to surrounding cells in tissues.
Extracellular matrix: The extracellular matrix (ECM) is a complex network of proteins and carbohydrates that provides structural and biochemical support to surrounding cells. It plays a crucial role in cell communication, differentiation, and the overall integrity of tissues, making it essential for maintaining tissue architecture and function.
Fascicles: Fascicles are bundles of muscle fibers (cells) found within skeletal muscle tissue, organized in a way that allows for efficient contraction and force generation. Each fascicle is surrounded by a connective tissue sheath called the perimysium, which helps to support and protect the muscle fibers while allowing them to work together effectively during movement.
Fibroblasts: Fibroblasts are a type of connective tissue cell that plays a critical role in the production and maintenance of the extracellular matrix, which provides structural support to tissues. These cells are responsible for synthesizing collagen and other fibers, making them essential for tissue repair and wound healing. Fibroblasts also contribute to the overall health and function of various tissues by secreting growth factors and cytokines that regulate inflammation and tissue remodeling.
Fibrocartilage: Fibrocartilage is a tough and dense type of cartilage that provides support and absorbs shock in various joints and structures in the body. It is characterized by its high content of collagen fibers, which give it strength and the ability to withstand pressure, making it essential for structures like intervertebral discs and pubic symphysis.
Fibrous connective tissues: Fibrous connective tissues are a type of connective tissue characterized by a high density of collagen fibers, which provide strength and support. These tissues are found in tendons, ligaments, and the dermis of the skin.
Gap junctions: Gap junctions are specialized intercellular connections that allow direct communication between adjacent cells by forming channels through which ions and small molecules can pass. These structures play a crucial role in coordinating cellular activities and maintaining tissue homeostasis, particularly in animal primary tissues such as cardiac muscle, where rapid electrical signaling is essential for proper function.
Glial cells: Glial cells are non-neuronal cells in the nervous system that provide support, protection, and nourishment to neurons. They play critical roles in maintaining homeostasis, forming myelin, and participating in signal transmission within the central nervous system and peripheral nervous system. While they do not transmit electrical impulses like neurons, glial cells are essential for the overall health and functioning of the nervous system.
Histology: Histology is the branch of biology that studies the microscopic structure of tissues. This field is essential for understanding how tissues are organized and function in multicellular organisms, providing insight into their roles in health and disease. Through histological techniques, scientists can visualize and analyze different types of tissues, which is critical for fields like medicine, pathology, and developmental biology.
Homeostasis: Homeostasis is the process by which biological systems maintain a stable internal environment despite external changes. This dynamic equilibrium is essential for the survival of organisms, as it regulates factors like temperature, pH, and the concentration of ions and nutrients. It connects to various aspects of biology, including how organisms interact with their environment and the physiological processes that sustain life.
Hyaline cartilage: Hyaline cartilage is a type of connective tissue characterized by its glassy, translucent appearance and a smooth surface. It serves various functions in the body, including providing support, flexibility, and cushioning at joints, as well as forming structures such as the trachea and the rib cage. This cartilage type is essential for the growth and development of long bones and plays a significant role in maintaining the structural integrity of various organs.
Intercalated discs: Intercalated discs are specialized structures that connect individual cardiac muscle cells (cardiomyocytes) in the heart. These discs contain gap junctions and desmosomes, allowing for synchronized contraction of the heart muscle and efficient transmission of electrical signals between cells. They play a crucial role in maintaining the functional integrity of cardiac tissue, enabling the heart to pump blood effectively.
Lacunae: Lacunae are small cavities within the bone matrix that house osteocytes. These spaces play a critical role in maintaining bone health and structure.
Leukocytes: Leukocytes, commonly known as white blood cells, are crucial components of the immune system responsible for defending the body against infections and foreign invaders. They play a vital role in identifying and eliminating pathogens, contributing to the body's ability to maintain homeostasis and health. Their diverse types, such as neutrophils, lymphocytes, and monocytes, have specialized functions that enhance the immune response.
Ligaments: Ligaments are tough bands of connective tissue that connect bones to other bones at joints, providing stability and support to the skeletal system. They play a crucial role in maintaining joint integrity and allowing for controlled movement by limiting excessive motion. Ligaments are essential in the structure of various skeletal systems and are key components in how joints function during movement.
Loose connective tissue: Loose connective tissue is a type of connective tissue that supports and surrounds other tissues and organs. It is characterized by a loose, irregular arrangement of fibers and abundant ground substance.
Matrix: A matrix is the non-cellular component of tissues that provides structural and biochemical support to surrounding cells. It consists of proteins, glycoproteins, and polysaccharides.
Microglia: Microglia are specialized glial cells in the central nervous system that act as the primary immune defense. They detect and respond to damage or infection by clearing debris and dead neurons.
Microglia: Microglia are the primary immune cells of the central nervous system (CNS) and play a crucial role in maintaining homeostasis, responding to injury, and protecting the brain from pathogens. They are specialized glial cells that act as the first line of defense in the CNS, constantly surveying the environment for signs of damage or infection. These cells also participate in neurodevelopmental processes and modulate neuronal activity, making them essential for both brain health and disease.
Myelin sheath: The myelin sheath is a protective layer of fatty material that surrounds the axons of neurons, enhancing the speed and efficiency of electrical signal transmission. This sheath is crucial for the proper functioning of the nervous system, as it allows for quicker communication between nerve cells by insulating axons and facilitating saltatory conduction, where action potentials jump between nodes of Ranvier.
Myocardium: Myocardium is the muscular middle layer of the heart wall, responsible for the heart's contractions and pumping blood throughout the body. This layer contains cardiac muscle tissue, which is unique in its ability to contract involuntarily and rhythmically, allowing the heart to function effectively as a pump. The myocardium plays a crucial role in maintaining circulation and is vital for overall cardiovascular health.
Neurons: Neurons are specialized cells in the nervous system that transmit information through electrical and chemical signals. They play a crucial role in communication within the body, allowing for responses to stimuli, coordination of actions, and integration of sensory information. Neurons consist of three main parts: the cell body, dendrites, and axon, which work together to facilitate the flow of information across neural networks.
Neurotransmitters: Neurotransmitters are chemical messengers that transmit signals across a synapse from one neuron to another, facilitating communication within the nervous system. They play crucial roles in influencing a wide range of physiological and psychological processes, including mood, perception, and muscle control.
Nodes of Ranvier: Nodes of Ranvier are small gaps in the myelin sheath of a neuron where the axon membrane is exposed, playing a critical role in the conduction of electrical signals along the nerve fibers. These nodes allow for saltatory conduction, which significantly speeds up the transmission of action potentials by enabling impulses to jump from one node to the next. This unique feature is essential for efficient communication within the nervous system.
Oligodendrocytes: Oligodendrocytes are a type of glial cell in the central nervous system that play a crucial role in supporting and insulating neurons. They are responsible for the formation of myelin sheaths, which wrap around axons to enhance the speed of electrical signal transmission. This myelination is vital for efficient communication within the nervous system and contributes to overall neural function.
Osteocytes: Osteocytes are mature bone cells that maintain the mineral content of the surrounding bone matrix. They are derived from osteoblasts and reside in small cavities called lacunae.
Osteocytes: Osteocytes are mature bone cells that play a critical role in maintaining bone tissue. They reside in small cavities called lacunae and extend long, hair-like processes through tiny channels known as canaliculi, allowing them to communicate with other bone cells. This communication is essential for regulating bone remodeling and maintaining the overall health and strength of the skeletal system.
Osteons: Osteons are cylindrical structures that form the functional unit of compact bone. They consist of concentric layers of calcified matrix and house blood vessels and nerves.
Perimysium: Perimysium is a type of connective tissue that surrounds and groups individual muscle fibers into bundles called fascicles within skeletal muscles. This structure not only provides support and protection but also allows for the efficient transmission of forces generated during muscle contractions. The perimysium contains blood vessels and nerves, which supply nutrients and signals to the muscle fibers it encloses.
Platelets: Platelets, also known as thrombocytes, are small, disc-shaped cell fragments in the blood that play a crucial role in hemostasis, the process of blood clotting. They are produced in the bone marrow and released into the bloodstream, where they help prevent excessive bleeding by adhering to sites of vascular injury and aggregating to form a temporary plug. This function is vital in maintaining vascular integrity and preventing blood loss from damaged blood vessels.
Proteoglycans: Proteoglycans are large molecules consisting of a core protein covalently bonded to one or more glycosaminoglycan (GAG) chains, which play crucial roles in the structure and function of various tissues. They are essential components of the extracellular matrix, providing support and hydration to tissues while also influencing cell signaling and interactions between cells.
Pseudostratified: Pseudostratified refers to a type of epithelial tissue where cells appear to be layered, but all cells are in contact with the basement membrane. This gives the illusion of stratification despite being a single layer.
Regeneration: Regeneration is the biological process by which organisms replace or restore lost or damaged tissues, organs, or body parts. This ability varies widely among different species, showcasing remarkable adaptations in certain groups to survive injury or predation while also playing a role in growth and development.
Reticular Tissue: Reticular tissue is a type of connective tissue that consists of a network of reticular fibers and cells that support the framework of various organs. This tissue plays a vital role in providing structural support, particularly in lymphoid organs like the spleen and lymph nodes, helping to filter and house immune cells.
Saltatory conduction: Saltatory conduction is a process by which nerve impulses jump from one node of Ranvier to another along myelinated axons, significantly increasing the speed of signal transmission. This mechanism allows for rapid communication between neurons and is crucial for efficient nervous system functioning, connecting to the structure of nerve cells and their supporting cells.
Sarcomeres: Sarcomeres are the basic contractile units of muscle fibers, consisting of repeating sections within myofibrils that are responsible for muscle contraction. These structures are composed of thick and thin filaments, primarily myosin and actin, which interact during contraction to shorten the muscle. Sarcomeres play a crucial role in the overall function of striated muscles, such as skeletal and cardiac muscle, impacting both movement and the pumping action of the heart.
Schwann cells: Schwann cells are specialized glial cells in the peripheral nervous system that play a critical role in the formation of myelin sheaths around axons. These cells not only facilitate the rapid conduction of nerve impulses but also support the regeneration of damaged nerves, making them essential for proper nervous system function.
Simple epithelia: Simple epithelia consist of a single layer of cells that cover surfaces or line cavities. They are specialized for functions such as absorption, secretion, and filtration.
Skeletal muscle: Skeletal muscle is a type of striated muscle tissue that is primarily responsible for voluntary movements in the body, attached to bones via tendons. It plays a crucial role in locomotion, posture, and body stability, while also contributing to the overall skeletal system by facilitating movement through contraction and relaxation.
Skeletal muscle tissue: Skeletal muscle tissue is a type of muscle tissue that is attached to bones and enables voluntary movement. It is composed of long, multinucleated fibers and exhibits striations under a microscope.
Smooth muscle: Smooth muscle is a type of involuntary, non-striated muscle found in various internal structures such as blood vessels and the digestive tract. Unlike skeletal muscle, smooth muscle cells are spindle-shaped and operate without conscious control, playing a crucial role in regulating bodily functions such as digestion and blood flow.
Smooth muscle tissue: Smooth muscle tissue is a type of muscle that is non-striated and involuntary, found primarily in the walls of hollow organs. It functions to propel substances through these organs via coordinated contractions.
Soma: Soma refers to the cell body of a neuron, which contains the nucleus and organelles essential for the cell's metabolic activities. It plays a critical role in integrating signals received from dendrites and generating action potentials that are transmitted along the axon. The soma is crucial for maintaining the overall health and function of the neuron, as it houses key components necessary for protein synthesis and cellular maintenance.
Spongy Bone: Spongy bone, also known as cancellous bone, is a type of bone tissue characterized by a porous, lattice-like structure that provides support and flexibility while reducing weight. This type of bone is typically found at the ends of long bones, within the interior of other bones, and in areas where lightness and strength are essential. Spongy bone contains red bone marrow, which is crucial for blood cell production, and plays an important role in overall skeletal health.
Squamous epithelial: Squamous epithelial cells are flat, scale-like cells that form the outer layer of epithelial tissue. They are specialized for diffusion and filtration due to their thin structure.
Stratified epithelia: Stratified epithelia are layers of epithelial cells stacked on top of each other. These tissues primarily serve protective functions and are commonly found in areas prone to abrasion.
Tendons: Tendons are strong connective tissues that attach muscles to bones, playing a crucial role in the movement of the skeletal system. They are composed primarily of collagen fibers, which provide them with tensile strength and resistance to stretching. Tendons enable the transfer of force generated by muscle contractions to the skeletal system, facilitating joint movement and overall locomotion.
Trabeculae: Trabeculae are the small, often microscopic, beam-like structures that form the spongy part of bone tissue. They provide structural support and help distribute loads in the bone.
Transitional: Transitional epithelium is a type of epithelial tissue specialized to stretch and recoil. It lines organs that need to expand, such as the bladder.