Human Body and Chemical Level Quiz

The four major tissue types are epithelial, connective, muscular, and nervous.

A negative feedback loop is a mechanism that counteracts a change in a controlled variable, bringing it back to a set point.

The major body systems involved in maintaining homeostasis include the nervous system, endocrine system, circulatory system, respiratory system, urinary system, and integumentary system.

<p>All of the above</p> Signup and view all the answers

<p>The major intracellular cations are potassium (K+) and magnesium (Mg2+), while the major intracellular anion is phosphate (PO43-). The major extracellular cation is sodium (Na+), and the major extracellular anion is chloride (Cl-).</p> Signup and view all the answers

<p>The plasma membrane encloses the cell, regulates the passage of molecules in and out of the cell, maintains cell shape, and participates in cell signaling.</p> Signup and view all the answers

<p>Mitochondria are responsible for energy production via ATP synthesis. ER is involved in protein synthesis, lipid synthesis, and detoxification. Ribosomes are involved in protein synthesis. Lysosomes degrade waste products and cellular debris. Golgi apparatus packages and modifies proteins. Centrioles are involved in cell division. The nucleus contains genetic material (DNA) and controls cellular activity. The nucleolus is involved in ribosome synthesis.</p> Signup and view all the answers

<p>Simple diffusion</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>The nucleolus is responsible for ribosome synthesis.</p> Signup and view all the answers

<p>The four major tissue types are epithelial, connective, muscular, and nervous. Epithelial tissue covers surfaces, lines cavities, and forms glands. Connective tissue supports and binds other tissues. Muscular tissue is responsible for movement. Nervous tissue transmits electrical signals throughout the body. Epithelial tissue is composed of tightly packed cells, while connective tissue has more dispersed cells. Muscular tissue is characterized by its ability to contract, and nervous tissue is composed of specialized cells that communicate via electrical impulses.</p> Signup and view all the answers

<p>Epithelial tissue is classified by the number of cell layers (simple or stratified) and the shape of the cells (squamous, cuboidal, or columnar). Simple epithelial tissue consists of a single layer of cells and is found lining body cavities, blood vessels, and the alveoli of the lungs. Stratified epithelial tissue consists of multiple layers of cells and is found in areas that experience abrasion, such as the skin, mouth, and esophagus. The function of epithelial tissue depends on its location and structure. Simple squamous epithelium is responsible for diffusion and filtration. Simple cuboidal epithelium is involved in secretion and absorption. Simple columnar epithelium is involved in secretion, absorption, and protection. Stratified squamous epithelium provides protection against abrasion. The structure of epithelial tissue is directly correlated with its function. For example, the thin, flat cells of simple squamous epithelium are well-suited for diffusion and filtration, while the multiple layers of stratified squamous epithelium provide protection against abrasion.</p> Signup and view all the answers

<p>Serous membranes line body cavities that do not open to the exterior, such as the pleura, pericardium, and peritoneum. Mucus membranes line cavities that open to the exterior, such as the respiratory tract, digestive tract, and urinary tract. Goblet cells are found in mucous membranes. They secrete mucus, which lubricates and protects the underlying tissues.</p> Signup and view all the answers

<p>Connective tissue is characterized by its dispersed cells, abundant extracellular matrix, and support and binding functions. The six types of CT proper are loose connective tissue, dense connective tissue, elastic connective tissue, reticular connective tissue, adipose tissue, and cartilage. Loose connective tissue is found beneath epithelial tissues and surrounds organs. Dense connective tissue is found in tendons, ligaments, and dermis of the skin. Elastic connective tissue is found in walls of blood vessels and lungs. Reticular connective tissue is found in lymph nodes, spleen, and bone marrow. Adipose tissue is found beneath the skin and around organs. Cartilage is found in the joints, nose, ears, and trachea. Other types of connective tissue include blood and bone. Blood is found in blood vessels, transporting oxygen, nutrients, and waste products. Bone provides support, protection, and attachment for muscles. The three types of cartilage are hyaline cartilage, elastic cartilage, and fibrocartilage. Hyaline cartilage is found in the nose, trachea, and articular surfaces of joints. Elastic cartilage is found in the ears and epiglottis. Fibrocartilage is found in intervertebral discs and menisci.</p> Signup and view all the answers

<p>Skeletal muscle is attached to bones and is responsible for voluntary movement. It is characterized by its striated appearance and multinucleated cells. Cardiac muscle is found only in the heart and is responsible for involuntary pumping of blood. It is characterized by its striated appearance and branched cells. Smooth muscle is found in the walls of internal organs, such as the digestive tract and blood vessels, and is responsible for involuntary movement. It is characterized by its non-striated appearance and spindle-shaped cells.</p> Signup and view all the answers

<p>The epidermis is composed of five layers: stratum corneum (outermost), stratum lucidum (only present in thick skin), stratum granulosum, stratum spinosum, and stratum basale (innermost). Keratinocytes are the most abundant cells in the epidermis. They produce keratin, a tough protein that provides protection for the skin. Melanocytes produce melanin, a pigment that gives skin its color and protects against UV radiation. Merkel cells are sensory receptors that detect touch. Langerhans cells are immune cells that help fight infection.</p> Signup and view all the answers

<p>The three layers of skin are the epidermis, dermis, and subcutaneous layer. The dermis contains blood vessels, nerves, sweat glands, hair follicles, and sebaceous glands. Blood vessels nourish the skin and help regulate body temperature. Nerves provide sensory input to the brain. Sweat glands help regulate body temperature. Hair follicles produce hair. Sebaceous glands secrete sebum, an oily substance that lubricates the skin. The dermal papillae, which are projections of the dermis into the epidermis, are responsible for fingerprints.</p> Signup and view all the answers

<p>The central nervous system (CNS) consists of the brain and spinal cord. The peripheral nervous system (PNS) consists of all the nerves that connect the CNS to the rest of the body.</p> Signup and view all the answers

<p>Nervous tissue is composed of neurons, which are specialized cells that transmit electrical signals, and neuroglia, which are supporting cells. The soma, or cell body, contains the nucleus and other organelles. The axon is a long, slender projection that transmits electrical signals away from the soma. The dendrite is a short, branched projection that receives electrical signals from other neurons.</p> Signup and view all the answers

<p>Neuroglia are supporting cells that provide structural and functional support to neurons. Astrocytes provide structural support to neurons, regulate the chemical environment of the brain, and help maintain the blood-brain barrier. Oligodendrocytes form the myelin sheath around axons in the CNS, which speeds up signal transmission. Schwann cells form the myelin sheath around axons in the PNS. Microglia are immune cells that phagocytize waste products and pathogens in the nervous system. Ependymal cells line the ventricles of the brain and the central canal of the spinal cord, producing cerebrospinal fluid.</p> Signup and view all the answers

<p>A neuron is a single nerve cell, while a nerve is a bundle of axons from many neurons.</p> Signup and view all the answers

<p>Gray matter is composed of neuron cell bodies, dendrites, and unmyelinated axons. It appears gray because it lacks myelin, which is a fatty substance that insulates axons. White matter is composed of myelinated axons. It appears white because of the myelin sheath. In the spinal cord, gray matter is found in the center and forms a butterfly-shaped structure. It is responsible for processing information and coordinating reflexes. White matter is found on the outside of the gray matter and carries signals between the brain and the rest of the body.</p> Signup and view all the answers

<p>The somatic nervous system controls voluntary movements, while the autonomic nervous system controls involuntary functions, such as heart rate, digestion, and breathing.</p> Signup and view all the answers

<p>The autonomic nervous system (ANS) is a part of the peripheral nervous system that controls involuntary functions, such as heart rate, digestion, and breathing. The ANS differs from the somatic nervous system in that it is not under conscious control. The ANS is divided into two divisions: the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system is responsible for the “fight-or-flight” response, while the parasympathetic nervous system is responsible for the “rest-and-digest” response. The sympathetic nervous system increases heart rate, dilates pupils, and stimulates the release of adrenaline. The parasympathetic nervous system slows heart rate, constricts pupils, and stimulates digestion.</p> Signup and view all the answers

<p>The external structures of the eye include the eyelids, eyelashes, conjunctiva, and lacrimal apparatus. The eyelids protect the eye from foreign objects and dust. The eyelashes help prevent dust and debris from entering the eye. The conjunctiva is a thin membrane that lines the inner surface of the eyelids and the outer surface of the eyeball. The lacrimal apparatus produces tears, which lubricate and cleanse the eye. Light first enters the eye through the cornea, which is a transparent, dome-shaped structure that helps to focus light. The light then passes through the pupil, which is an opening in the iris. The iris is a colored muscular structure that controls the amount of light entering the eye. The light then passes through the lens, which is a transparent, elastic structure that further focuses light onto the retina. The retina is the light-sensitive lining of the back of the eye. Light then passes through the optic nerve, which carries signals from the retina to the brain.</p> Signup and view all the answers

<p>The retina contains two types of photoreceptor cells: rods and cones. Rods are more sensitive to light and are responsible for vision in dim light. Cones are less sensitive to light but are responsible for color vision and sharp vision in bright light. Rods contain a pigment called rhodopsin, which is sensitive to low levels of light. Cones contain three types of pigments, each of which is sensitive to a different wavelength of light. Rods are more numerous than cones. The distribution of rods and cones varies across the retina. The fovea, which is a small pit in the center of the retina, contains only cones. The peripheral retina contains both rods and cones, but rods are more numerous. The function of rods is to detect light and dark. The function of cones is to detect color and detail. The difference in acuity of rods and cones is due to their different levels of sensitivity to light and their different distributions in the retina.</p> Signup and view all the answers

<p>The outer ear consists of the pinna, auditory canal, and tympanic membrane. The pinna is the visible part of the ear that collects sound waves. The auditory canal is a narrow tube that directs sound waves to the tympanic membrane. The tympanic membrane is a thin, oval-shaped membrane that vibrates in response to sound waves. The middle ear consists of the ossicles (malleus, incus, and stapes) and the Eustachian tube. The ossicles are three small bones that transmit vibrations from the tympanic membrane to the oval window. The Eustachian tube connects the middle ear to the back of the throat and helps to regulate pressure in the middle ear. The inner ear consists of the cochlea, semicircular canals, and vestibule. The cochlea is a spiral-shaped structure that contains the organ of Corti, which is responsible for hearing. The semicircular canals are three fluid-filled canals that are responsible for balance. The vestibule is a chamber between the cochlea and semicircular canals that contains sensory receptors for balance.</p> Signup and view all the answers

<p>The utricle and saccule are responsible for detecting linear acceleration and gravity. The semicircular canals are responsible for detecting rotational movement. The organ of Corti is responsible for converting sound waves into electrical signals that are sent to the brain.</p> Signup and view all the answers

<p>Bones can be classified by their shape into four categories: long bones, short bones, flat bones, and irregular bones. Long bones are longer than they are wide and have a shaft (diaphysis) and two ends (epiphyses). Examples of long bones include the femur, tibia, fibula, humerus, radius, and ulna. Short bones are roughly cube-shaped and are found in the wrist and ankle. Flat bones are thin and flattened and serve as protection. Examples of flat bones include the skull, ribs, sternum, and scapula. Irregular bones have complex shapes and do not fit into any of the other categories. Examples of irregular bones include the vertebrae, facial bones, and hip bones.</p> Signup and view all the answers

<p>The diaphysis is the shaft of the bone. The epiphyses are the ends of the bone. The epiphyseal plate is a layer of hyaline cartilage that separates the diaphysis from the epiphyses in a growing bone. The periosteum is a tough, fibrous membrane that covers the outside of the bone. The endosteum is a thin membrane that lines the inside of the bone. The medullary cavity is the hollow space within the diaphysis that contains bone marrow. The articular cartilage is a smooth, white layer of cartilage that covers the ends of the bone where it forms a joint.</p> Signup and view all the answers

<p>Osteoblasts are cells that form new bone tissue. Osteocytes are mature bone cells that maintain bone tissue. Osteoclasts are cells that break down bone tissue. Chondrocytes are cells that form cartilage.</p> Signup and view all the answers

<p>Compact bone is characterized by its dense, solid structure. The basic functional unit of compact bone is the osteon, which is a cylindrical structure that consists of concentric lamellae, a central canal, lacunae, and canaliculi. Lamellae are thin layers of bone matrix. The central canal contains blood vessels, nerves, and lymphatic vessels that supply the osteon. Lacunae are small spaces that contain osteocytes. Canaliculi are tiny canals that connect lacunae to the central canal, allowing for the passage of nutrients and wastes to osteocytes.</p> Signup and view all the answers

<p>Compact bone is dense and solid, while spongy bone is lighter and more porous. Compact bone is found in the shafts of long bones, while spongy bone is found in the ends of long bones and in flat bones. Compact bone is strong and provides support, while spongy bone is less strong but is more flexible. Compact bone is made up of osteons, which are cylindrical units of bone tissue. Spongy bone is made up of trabeculae, which are thin, bony plates.</p> Signup and view all the answers

<p>Red bone marrow is located in the spaces between the trabeculae of spongy bone.</p> Signup and view all the answers

<p>Calcium is stored in bone as hydroxyapatite crystals. When blood calcium levels are low, parathyroid hormone (PTH) is released from the parathyroid glands. PTH stimulates osteoclasts to break down bone tissue, releasing calcium into the bloodstream. When blood calcium levels are high, calcitonin is released from the thyroid gland. Calcitonin inhibits osteoclast activity and promotes calcium deposition in bone.</p> Signup and view all the answers

<p>Bone remodeling is a continuous process of bone breakdown and formation. It is important for maintaining bone strength and integrity, repairing bone injuries, and adapting bone shape and size to changes in stress. Bone remodeling is affected by a variety of factors, including age, diet, hormones, and physical activity.</p> Signup and view all the answers

<p>The axial skeleton consists of the bones that form the central axis of the body. These include the skull, vertebral column, ribs, and sternum. The appendicular skeleton consists of the bones of the limbs, pectoral girdle (scapulae and clavicles), and pelvic girdle (hip bones).</p> Signup and view all the answers

<p>Bony markings are surface features on bones that serve as attachment points for muscles, tendons, and ligaments, or provide passageways for blood vessels and nerves. Bony markings include projections, depressions, and openings. Projections are bumps or ridges that serve as attachment points for muscles and tendons. Depressions are indentations or grooves that house tendons and ligaments. Openings are holes or canals that allow for the passage of blood vessels, nerves, and ligaments.</p> Signup and view all the answers

<p>Joints, or articulations, are the points where two or more bones meet. Joints are classified into three major classes based on their degree of movement: fibrous joints, cartilaginous joints, and synovial joints. Fibrous joints are immovable and are held together by fibrous connective tissue. Examples include the sutures of the skull. Cartilaginous joints are slightly movable and are held together by cartilage. Examples include the joints between the vertebrae. Synovial joints are freely movable and are characterized by a joint capsule, synovial fluid, and articular cartilage. The six types of synovial joints are: 1) Plane joints: allow for gliding movements. Examples include the joints between the carpals and tarsals. 2) Hinge joints: allow for flexion and extension movements. Examples include the elbow and knee joints. 3) Pivot joints: allow for rotation movements. Examples include the joint between the radius and ulna. 4) Condyloid joints: allow for flexion, extension, abduction, adduction, and circumduction movements. Examples include the joints between the metacarpals and phalanges. 5) Saddle joints: allow for flexion, extension, abduction, adduction, and circumduction movements. Examples include the joint between the thumb and the carpal bones. 6) Ball-and-socket joints: allow for the greatest range of motion, including flexion, extension, abduction, adduction, rotation, and circumduction movements. Examples include the shoulder and hip joints.</p> Signup and view all the answers

<p>Skeletal muscle cells, or muscle fibers, are composed of myofibrils, which are long cylindrical structures that run the length of the cell. Myofibrils are made up of repeating units called sarcomeres. A sarcomere is the basic functional unit of a muscle fiber. It is bounded by two Z discs, which are protein structures that anchor the thin filaments. The sarcomere contains both thin filaments, which are made up of the protein actin, and thick filaments, which are made up of the protein myosin. The thick and thin filaments are arranged in a repeating pattern, creating the striated appearance of skeletal muscle.</p> Signup and view all the answers

<p>The Sliding Filament Theory explains muscle contraction. It states that muscle contraction occurs when the thin filaments slide past the thick filaments, shortening the sarcomere. The neurological events leading up to muscle contraction are as follows: 1) An action potential travels down a motor neuron axon. 2) The action potential reaches the neuromuscular junction, where the motor neuron releases acetylcholine. 3) Acetylcholine binds to receptors on the muscle fiber membrane, triggering a depolarization. 4) The depolarization spreads throughout the muscle fiber, causing the release of calcium from the sarcoplasmic reticulum. 5) Calcium binds to troponin on the thin filaments, exposing the myosin-binding sites on actin. 6) Myosin heads bind to actin and pull on the thin filaments, causing the sarcomere to shorten. 7) The muscle fiber contracts. 8) Acetylcholine is broken down by acetylcholinesterase, ending the signal. 9) Calcium is pumped back into the sarcoplasmic reticulum, causing the myosin-binding sites on actin to be covered again, and the muscle fiber relaxes.</p> Signup and view all the answers

<p>Excitation-contraction coupling refers to the process by which a nerve impulse is transmitted to a muscle fiber, causing it to contract.</p> Signup and view all the answers

<p>A motor unit is a single motor neuron and all of the muscle fibers that it innervates. The number of muscle fibers in a motor unit varies depending on the muscle. Fine motor movements, such as those of the eye, are controlled by motor units with a small number of muscle fibers. Coarse motor movements, such as those of the leg, are controlled by motor units with a large number of muscle fibers.</p> Signup and view all the answers

<p>The major muscles of the body can be classified into groups according to their location and function: Head and Neck: Facial muscles: control facial expressions. Masseter: elevates the mandible for chewing. Temporalis: elevates and retracts the mandible for chewing. Sternocleidomastoid: flexes the head and rotates the head toward the opposite side. Trapezius: elevates, depresses, adducts, and rotates the scapula.</p> Signup and view all the answers