MBLEx Anatomy And Physiology Exam Practice Quiz!

Type O blood is considered the universal donor because it lacks both A and B antigens on the red blood cells. This means that it can be transfused to individuals with any blood type without causing an immune reaction. Individuals with type O blood are often encouraged to donate blood as it can be used in emergencies when the recipient's blood type is unknown or when there is a shortage of compatible blood types.

The vocal cords are located in the larynx. The larynx, also known as the voice box, is a part of the respiratory system located in the neck. It houses the vocal cords, which are folds of tissue that vibrate to produce sound when air passes through them. The larynx also plays a role in protecting the airway during swallowing by closing off the entrance to the trachea with the epiglottis.

A ball-like, masticated lump of food once swallowed is referred to as a bolus. After chewing and mixing with saliva, the food forms into a compact mass that can be easily swallowed and transported through the esophagus into the stomach. The term "bolus" is commonly used in the context of digestion and the movement of food through the digestive system.

The liver is located in the right upper quadrant of the abdomen. This is because the liver is the largest solid organ in the body and is situated on the right side, just below the diaphragm. It extends from the right upper quadrant towards the middle of the abdomen. The other quadrants mentioned in the options do not contain the liver.

Pronation refers to the medial or inward rotation of the forearm. This movement occurs when the palm of the hand is turned downward or backward. It involves the rotation of the radius bone around the ulna bone, resulting in the crossing of the two bones. Pronation is commonly observed when performing activities such as turning a doorknob or pouring water from a jug.

Smooth muscle is the correct answer because it consumes very little energy compared to skeletal and cardiac muscles. Smooth muscles are found in the walls of organs and blood vessels, and their contractions are slow and sustained. These muscles are responsible for involuntary movements, such as the movement of food through the digestive tract. Unlike skeletal muscles that require a lot of energy for rapid and forceful contractions, smooth muscles have a slower metabolism and can maintain a low level of energy consumption over a longer period of time.

Internal respiration refers to the process of gas exchange that occurs at the cellular level within the body. It involves the exchange of oxygen and carbon dioxide between the bloodstream and the cells. This process takes place in the tissues and is essential for cellular metabolism and energy production. External respiration, on the other hand, refers to the exchange of gases between the external environment and the lungs. Therefore, the correct answer is internal respiration, as it specifically relates to the exchange of gases at the cellular level.

The superior hollow heart chambers are the atria. The atria receive blood returning to the heart and then pump it into the ventricles. They are located at the top of the heart and are smaller and thinner-walled compared to the ventricles. The ventricles, on the other hand, are the lower chambers of the heart and are responsible for pumping blood out of the heart to the rest of the body. Bladders and papilla are not related to the heart chambers and are not relevant to the question.

The correct answer is Duodenum. The duodenum is the first section of the small intestines. It is responsible for receiving partially digested food from the stomach and further breaking it down with the help of enzymes from the pancreas and bile from the liver.

The skeletal system plays a crucial role in maintaining mineral balance in the body. It stores minerals such as calcium and phosphorus, which are essential for various bodily functions. When the body needs these minerals, the skeletal system releases them into the bloodstream. This process helps maintain the mineral levels required for vital functions like muscle contraction, nerve transmission, and blood clotting. Therefore, the statement that the skeletal system restores vital minerals is true.

Smooth muscle is the correct answer because it is also referred to as visceral muscle. Smooth muscle is found in the walls of organs and structures such as the intestines, blood vessels, and uterus. It is called smooth muscle because its cells lack striations, giving it a smooth appearance under a microscope. Smooth muscle is involuntary, meaning it is not under conscious control. It contracts and relaxes slowly and rhythmically, allowing for functions such as digestion, blood flow regulation, and childbirth.

Internal respiration refers to the process by which carbon dioxide (CO2) diffuses from the cells into the bloodstream. This occurs in the tissues of the body, where cells produce CO2 as a waste product of cellular respiration. The CO2 then diffuses across the cell membranes and into the surrounding capillaries, where it binds to hemoglobin or dissolves in the plasma for transport back to the lungs. Therefore, internal respiration is the correct term for the described process.

The given statement is false. The bones of the skull, thorax, and vertebral column, along with the hyoid bone, actually comprise the axial skeleton, not the appendicular skeleton. The appendicular skeleton consists of the bones of the upper and lower limbs, including the shoulder and pelvic girdles.

The stomach is a J-shaped organ that is bound at both ends by sphincters. The lower esophageal sphincter separates the stomach from the esophagus, while the pyloric sphincter separates the stomach from the small intestine. These sphincters help regulate the movement of food into and out of the stomach, allowing for digestion and preventing backflow of stomach acid into the esophagus. Therefore, the stomach is the correct answer in this case.

The dermis is the correct answer because it is the layer of skin that contains blood vessels, many nerve receptors, hair follicles, and skin glands. The dermis is located beneath the epidermis and provides support and nourishment to the skin. It is responsible for regulating body temperature, sensing touch, and producing sweat and oil.

Myosin is the correct answer because it is a thick myofilament found in muscle fibers. It is responsible for the contraction of muscles by interacting with actin, a thin myofilament. Myosin molecules have a long tail and a globular head that binds to actin, forming cross-bridges. These cross-bridges undergo a series of chemical reactions that generate the force required for muscle contraction. Therefore, myosin plays a crucial role in muscle function and is the thick myofilament in this context.

The two ends of a sarcomere are called Z-lines. These structures mark the boundaries of the sarcomere and are responsible for anchoring the actin filaments. During muscle contraction, the Z-lines move closer together, causing the sarcomere to shorten. Therefore, Z-lines play a crucial role in the contraction and relaxation of muscles.

Blood is slightly alkaline, not acidic. The pH of blood is typically around 7.4, which is slightly alkaline. This alkaline pH is important for maintaining proper functioning of enzymes and other biochemical processes in the body.

External respiration refers to the exchange of gases between the lungs and the external environment. In this process, oxygen is taken in from the air into the alveoli of the lungs, while carbon dioxide, a waste product, is diffused from the blood across the alveolar walls into the air inside the alveoli. This carbon dioxide is then exhaled out of the body. Therefore, the given explanation aligns with the concept of external respiration.

The vermiform appendix is suspended from the inferior portion of the cecum. The appendix is a small, finger-like pouch attached to the cecum, which is the first part of the large intestine. It hangs down from the cecum and is typically located in the lower right quadrant of the abdomen. The appendix does not have a known function in humans and can sometimes become inflamed or infected, leading to a condition called appendicitis.

A skeletal muscle is a muscle cell that contains bands of red and white material, causing it to appear striated. This type of muscle is responsible for voluntary movements in the body, such as walking and lifting weights. It is attached to bones by tendons and is under conscious control. Smooth muscle, on the other hand, does not have the same striated appearance and is found in organs like the stomach and intestines. Cardiac muscle is specific to the heart and also appears striated, but it has different characteristics compared to skeletal muscle.

The dermis is known as the true skin because it is the layer of skin that lies beneath the epidermis and is responsible for providing strength, elasticity, and support to the skin. It contains various structures such as blood vessels, nerve endings, sweat glands, and hair follicles. The dermis also plays a crucial role in regulating body temperature and protecting the body from external threats.

The epidermis is the outermost layer of the skin and is relatively avascular, meaning it lacks blood vessels. It is primarily composed of keratinocytes, which are responsible for producing the protein keratin that provides strength and waterproofing to the skin. The lack of blood vessels in the epidermis is important for its main function of protecting the body from external factors such as pathogens and UV radiation. The dermis, on the other hand, is highly vascularized and contains blood vessels, nerves, and other structures. The hypodermis is also vascularized and contains adipose tissue and blood vessels. The endodermis is not a skin region but rather a layer of cells in plant roots.

The correct answer is Sliding filament theory. This theory explains how filaments within the sarcomere slide past each other in order to create a change in muscle length. According to this theory, during muscle contraction, the thin actin filaments slide over the thick myosin filaments, causing the sarcomere to shorten. This sliding of filaments is facilitated by the interaction between the myosin heads and actin, which results in the formation of cross-bridges and the subsequent pulling of actin filaments towards the center of the sarcomere. This theory is widely accepted and supported by experimental evidence.

Actin is the correct answer because it is a protein that forms the thin filaments in muscle cells. These thin filaments interact with thick filaments made of myosin to generate muscle contractions. Epimysium is a connective tissue that surrounds the entire muscle, while fasciculi are bundles of muscle fibers. Therefore, Actin is the only option that represents the thin myofilament.

Type AB is called the universal recipient because individuals with this blood type can receive blood from any of the other blood types (A, B, or O) without experiencing an adverse immune response. This is because type AB blood has both A and B antigens on its red blood cells, and therefore does not produce antibodies against either A or B antigens. As a result, type AB individuals can safely receive transfusions of any ABO blood type.

The correct answer is Chemicals, cells, tissues, organs, organ systems, organism. This is the proper order from least complex to most complex in terms of biological organization. Chemicals are the basic building blocks of life, followed by cells which are made up of chemicals. Tissues are formed by groups of cells working together, organs are made up of different tissues working together, and organ systems are composed of multiple organs working together. Finally, an organism is the highest level of biological organization, consisting of all the organ systems working together to maintain life.

The epiglottis is referred to as the guardian of the airways because it is a flap of cartilage located at the base of the tongue that prevents food and liquid from entering the trachea during swallowing. It covers the opening of the larynx, ensuring that only air can pass through to the lungs while eating and drinking. This mechanism helps to protect the respiratory system from potential choking hazards.

The right atrium receives blood from the superior and inferior vena canae and the coronary sinus. This is because the superior vena cava brings deoxygenated blood from the upper body, the inferior vena cava brings deoxygenated blood from the lower body, and the coronary sinus brings deoxygenated blood from the heart muscle itself. The right atrium then pumps this deoxygenated blood into the right ventricle, which will eventually pump it to the lungs for oxygenation.

The sarcoplasmic reticulum is a specialized organelle in muscle cells that stores and releases calcium ions. Calcium plays a crucial role in muscle contraction by binding to proteins within the muscle fibers, allowing them to slide past each other and generate force. When a muscle is stimulated to contract, calcium is released from the sarcoplasmic reticulum into the surrounding muscle fibers, initiating the contraction process. Therefore, the correct answer is calcium.

External respiration is the process of exchanging oxygen and carbon dioxide between the lungs and the external environment. It involves the inhalation of oxygen-rich air into the lungs and the exhalation of carbon dioxide from the lungs. This process occurs in the alveoli, tiny air sacs in the lungs, where oxygen from the inhaled air diffuses into the bloodstream and carbon dioxide from the bloodstream diffuses into the alveoli to be exhaled. Internal respiration, on the other hand, refers to the exchange of gases between the bloodstream and the body's tissues.

Diarthrotic joints are freely movable joints. These joints allow for a wide range of motion and are found in areas such as the shoulder, hip, and knee. Synarthrotic joints are immovable joints, while amphiarthrotic joints allow for limited movement. Triarthrotic is not a recognized classification for joints. Therefore, the correct classification for freely movable joints is diarthrotic.

The left atrioventricular valve, also known as the mitral valve, is the bicuspid valve. This valve is located between the left atrium and the left ventricle of the heart. It consists of two flaps or cusps that open and close to regulate blood flow from the atrium to the ventricle. The tricuspid valve is located on the right side of the heart, while the pulmonary semilunar valve is located in the pulmonary artery. The "tricycle valve" is not a known valve in the human heart.

External respiration refers to the process of exchanging oxygen and carbon dioxide between the lungs and the external environment. It involves the inhalation of oxygen-rich air into the lungs, where it diffuses into the bloodstream and is transported to the body's tissues. At the same time, carbon dioxide, a waste product of cellular respiration, is removed from the bloodstream and exhaled out of the lungs. Therefore, respiration that occurs in the lungs is correctly referred to as external respiration.

External respiration refers to the process of gas exchange that occurs between the blood and the air in the alveoli. During external respiration, oxygen from the inhaled air diffuses into the bloodstream while carbon dioxide, a waste product, is removed from the blood and exhaled. This process takes place in the lungs, specifically in the tiny air sacs called alveoli, where the thin walls allow for efficient exchange of gases between the air and the bloodstream. Internal respiration, on the other hand, refers to the exchange of gases that occurs at the cellular level within the body's tissues.

Collagen and elastin are found in the dermis layer of the skin. The dermis is the middle layer of the skin, located between the epidermis (outer layer) and the hypodermis (innermost layer). Collagen provides structural support and strength to the skin, while elastin allows the skin to stretch and recoil. These proteins are essential for maintaining the elasticity, firmness, and overall health of the skin.

Plasma is the liquid component of blood that carries various substances such as nutrients, hormones, and waste products. It makes up about 55% of the total blood volume. This is because plasma is the largest component of blood and occupies a significant portion of the blood volume, while the remaining percentage is made up of red and white blood cells, platelets, and other cellular components.

Stroke volume is the amount of blood that is ejected from the left ventricle of the heart during each contraction. It represents the volume of blood that is pumped out of the heart and into the circulation with each heartbeat. This is an important measure of cardiac function and is influenced by factors such as heart rate, preload, and afterload.

Skeletal muscle is the correct answer because it is the only type of muscle cell that is multinucleated. Smooth muscle cells and cardiac muscle cells are both uninucleated, meaning they only have one nucleus. Skeletal muscle cells, on the other hand, have multiple nuclei, which allows them to generate more protein and contract with greater force. This multinucleation is a unique characteristic of skeletal muscle cells and is essential for their function in voluntary movement.

Skeletal muscle is the correct answer because it is the only type of muscle cell that is cigar-shaped. Smooth muscle cells are spindle-shaped, while cardiac muscle cells are branched. Skeletal muscle cells, also known as striated muscle cells, have a long and cylindrical shape, resembling a cigar.

The right atrium receives blood from all parts of the body except the lungs. This is because the right atrium receives deoxygenated blood from the superior and inferior vena cava, which collect blood from the systemic circulation. The deoxygenated blood is then pumped into the right ventricle, which will eventually pump it to the lungs for oxygenation. Therefore, the correct answer is the right atrium.

The correct answer is "Hypodermis". The hypodermis is another term used to describe the subcutaneous layer. It is the deepest layer of the skin and is composed of fat cells and connective tissue. The hypodermis helps to insulate the body, store energy, and cushion organs and tissues.

Epimysium is the correct answer because it is the fascial covering that surrounds the entire muscle. It is a dense connective tissue layer that provides protection and support to the muscle, helping to maintain its shape and integrity. Epimysium also connects the muscle to the surrounding structures, allowing for coordinated movement and transmission of forces.

The medullary cavity is the correct answer. It is the hollow space within the center of the diaphysis, which is the long shaft of a bone. This cavity contains bone marrow, which is responsible for producing blood cells. The medullary cavity is surrounded by compact bone and provides structural support to the bone while also allowing for the storage of minerals.

Volkman's canal is the correct answer because it is a system of canals that connects to Haversian canals and runs horizontally through bone. Haversian canals are small channels in the bone that contain blood vessels and nerves, and Volkman's canals provide a means for these blood vessels and nerves to travel horizontally through the bone, connecting different Haversian canals. The other options, Golgi canal, osteal canal, and medullary canal, are not associated with connecting to Haversian canals or running horizontally through bone.

Goblet cells are responsible for producing mucus. Mucus is a thick, sticky substance that helps to lubricate and protect the lining of various organs and tissues in the body. Goblet cells are found in the respiratory tract, digestive tract, and other mucous membranes throughout the body. They secrete mucus, which helps to trap and remove foreign particles, bacteria, and other potential harmful substances. This helps to maintain the health and function of the organs and tissues where goblet cells are present.

The cardioesophageal sphincter is found at the junction between the esophagus and stomach. This sphincter acts as a valve, allowing food to pass from the esophagus into the stomach and preventing stomach acid from flowing back up into the esophagus. It helps to regulate the movement of food and prevents acid reflux, which can cause heartburn and other symptoms.

The aortic semilunar valve is the correct answer because it is the valve that separates the left ventricle from the aorta. This valve prevents the backflow of blood from the aorta into the left ventricle when the ventricle relaxes.

Cardiac muscle cells have a unique structure that resembles the shape of a "Y" or "H". This distinct shape allows the cells to tightly connect with each other, forming a strong network that can withstand the constant contraction and relaxation required for the heart to pump blood effectively. Unlike smooth muscle cells, which have a spindle-like shape, and skeletal muscle cells, which are long and cylindrical, the cardiac muscle cells' "Y" or "H" shape is specific to the heart and enables synchronized contractions for efficient pumping.

Skeletal muscle is the correct answer because it is the only type of muscle cell that has many nuclei located near the periphery of the cell. Smooth muscle cells have a single nucleus and cardiac muscle cells have one or two centrally located nuclei. Skeletal muscle cells, on the other hand, are long and cylindrical in shape with multiple nuclei located at the periphery, giving them a striated appearance. This arrangement allows for efficient contraction and movement of the skeletal muscles.

Krause end bulbs are often called the "cold receptors" because they are sensitive to cold temperatures. These receptors are located in the skin and help detect changes in temperature, particularly cold sensations. They are responsible for sending signals to the brain when the skin comes into contact with cold objects or environments, allowing us to perceive and respond to cold stimuli.

The statement is false because the axial skeleton only includes the skull, vertebral column, and rib cage. The shoulder girdle and pelvic girdle are actually part of the appendicular skeleton, which includes the limbs and the bones that connect them to the axial skeleton.

Haversian canals are minute vascular canals that run longitudinally down the bone. They contain blood vessels, nerves, and connective tissue, and they are responsible for supplying nutrients and removing waste products from the bone tissue. Haversian canals are found in compact bone and are surrounded by concentric layers of bone tissue called lamellae.

The left ventricle is responsible for pumping oxygenated blood from the heart to the rest of the body through the aorta. It is the thickest and strongest chamber of the heart, as it needs to generate enough force to push blood throughout the entire circulatory system. The left ventricle receives oxygen-rich blood from the left atrium and contracts to push the blood out into the aorta, which then distributes it to the rest of the body.

The left atrium receives blood from the pulmonary veins. The pulmonary veins carry oxygenated blood from the lungs back to the heart. Once in the left atrium, the blood is then pumped into the left ventricle, which will eventually pump it out to the rest of the body. The left atrium acts as a holding chamber for oxygenated blood before it is sent to be distributed throughout the body.

External respiration refers to the process of exchanging gases between the external environment and the lungs. In this case, oxygen from the air inside the alveoli diffuses across the alveolar walls into the blood capillaries, while carbon dioxide moves in the opposite direction. This process occurs in the lungs and is essential for the uptake of oxygen and elimination of carbon dioxide from the body. Internal respiration, on the other hand, refers to the exchange of gases between the blood and body tissues at the cellular level.

Cardiac muscle is the correct answer because it is the only type of muscle cell that contains one oval-shaped nucleus. Smooth muscle cells have a single nucleus, but it is not oval-shaped. Skeletal muscle cells have multiple nuclei, and their shape can vary. Cardiac muscle cells have a single nucleus that is oval-shaped, making them unique among the three options.

The left ventricle is responsible for pumping oxygenated blood to the rest of the body. It has the thickest wall compared to the other chambers of the heart because it needs to generate enough force to push the blood against the high resistance of the systemic circulation. The left ventricle receives oxygen-rich blood from the left atrium and contracts forcefully to propel it into the aorta, which then distributes the blood to all the organs and tissues of the body.

The synonym for throat is pharynx. The pharynx is a muscular tube that connects the nasal cavity and mouth to the esophagus and larynx. It is an important part of the respiratory and digestive systems. The trachea, epiglottis, and larynx are all structures that are located within or connected to the pharynx, but they are not direct synonyms for the term "throat."

The right ventricle is responsible for pumping blood through the pulmonary trunk and into the pulmonary arteries. This is because the right ventricle receives deoxygenated blood from the right atrium and then contracts to push the blood out of the heart and into the lungs for oxygenation. The oxygenated blood is then returned to the left atrium and ventricle for distribution to the rest of the body.

Cardiac muscle is the correct answer because it is the only type of muscle that contains intercalated disks between each muscle cell. These intercalated disks allow for synchronized contractions of the cardiac muscle cells, ensuring efficient pumping of blood throughout the body. Smooth muscle does not have intercalated disks, and skeletal muscle is composed of individual muscle fibers that are not connected by intercalated disks. Therefore, cardiac muscle is the only type of muscle that fits the description provided.

Smooth muscle cells are characterized by their spindle-shaped morphology, with pointed ends. These cells are found in the walls of various organs and structures, such as blood vessels, the digestive tract, and the respiratory system. Smooth muscle is responsible for involuntary movements and contractions, controlling functions like blood flow, peristalsis, and airway diameter. Unlike skeletal and cardiac muscle, smooth muscle lacks striations and is not under conscious control. Therefore, the correct answer is smooth muscle.

Smooth muscle cells are adapted for long, sustained contractions. This is because smooth muscle is found in organs such as the intestines, blood vessels, and uterus, where contractions need to be maintained for extended periods of time. Smooth muscle cells have a unique arrangement of actin and myosin filaments that allows them to contract and relax slowly and rhythmically. Additionally, smooth muscle cells have a high resistance to fatigue, enabling them to sustain contractions for prolonged periods without tiring.

Cardiac muscle cells have a unique branching shape that allows them to fit together and create the spherical shape of a hollow organ, such as the heart. This arrangement enables the cardiac muscle to contract and pump blood effectively throughout the body. Unlike skeletal muscle cells, which are long and cylindrical, and smooth muscle cells, which are spindle-shaped, the branching structure of cardiac muscle cells allows for synchronized contraction and relaxation, ensuring efficient and coordinated pumping action.

The intercartilaginous ligament does not exist. It is not a recognized ligament in the human body. Therefore, the statement that it is a tough membrane that interconnects select bones and attaches to their periosteum is false.