1st Year Physiology Quiz Exam!

The brain receives approximately 20% of the cardiac output. This means that out of the total amount of blood pumped by the heart, 20% of it is directed towards supplying oxygen and nutrients to the brain. The brain is a highly metabolically active organ and requires a constant supply of blood to function properly. The brain's high demand for blood is due to its role in controlling various bodily functions and maintaining homeostasis.

The pacinian corpuscle is a rapidly adapting receptor, not a slowly adapting receptor. It consists of a layered structure resembling an onion and is responsible for detecting pressure. It is found subcutaneously in the skin.

Ionic concentration gradients are maintained across the cell membrane because membrane pumps move different ions into and out of the cell. These pumps actively transport ions against their concentration gradients, using ATP energy. This process helps to establish and maintain a higher concentration of certain ions on one side of the membrane compared to the other. This concentration gradient is essential for various cellular processes, such as nerve impulse transmission, muscle contraction, and nutrient uptake.

During prophase, the nucleoli start to disappear and the chromosomes become visible. This is the first stage of mitosis where the genetic material in the cell condenses and becomes more compact. The disappearance of nucleoli indicates the start of the breakdown of the nucleus, while the appearance of chromosomes signifies the condensation of DNA into visible structures. Therefore, prophase is the correct answer as it describes the stage where these changes occur.

The given description matches the function of the cerebellum. The cerebellum is responsible for coordinating movement and speech, controlling balance and posture, and controlling eye movement. It plays a crucial role in motor control and coordination.

Mitosis is the correct answer because it is the process by which cells divide and replicate, allowing for growth and repair in the body. During mitosis, a single cell divides into two identical daughter cells, each with the same number of chromosomes as the parent cell. This process is essential for the development and maintenance of tissues and organs in the body. Meiosis, on the other hand, is a specialized cell division process that occurs in reproductive cells to produce gametes (sperm and eggs) with half the number of chromosomes. Therefore, meiosis is not involved in the normal growth and repair of the body.

All of the above options require a concentration gradient in order to occur. Simple diffusion is the movement of molecules from an area of high concentration to an area of low concentration, and this process relies on the presence of a concentration gradient. Similarly, dissolving in the lipid portion of the membrane and carrier-mediated (facilitated) diffusion also require a concentration gradient for molecules to move across the membrane. Therefore, all of these processes depend on the existence of a concentration gradient.

Sensory information from receptors in the body travels up the spinal cord to the brain along two main routes: the spinothalamic tract and the posterior column tract. The spinothalamic tract carries information about pain, temperature, and crude touch, while the posterior column tract carries information about fine touch, proprioception, and vibration. These two routes are responsible for transmitting sensory information to different areas of the brain for processing and interpretation.

The given answer suggests that "reaching a threshold" is the correct explanation. This implies that the process described in the previous statements (potassium diffusing out of the cell, sodium diffusing into the cell, sodium gates closing/potassium gates opening) leads to a point where a threshold is reached. This threshold could refer to a certain level of membrane potential or activation that triggers a specific response or action in the cell.

During mitotic cell division, the chromosomes migrate towards the poles of the cell. Centrioles are responsible for organizing the spindle fibers, which help in the movement of chromosomes. They are located near the nucleus and play a crucial role in ensuring the accurate separation of chromosomes during cell division. Therefore, centrioles become the poles of the cell to which chromosomes migrate during mitotic cell division.

Interferons are proteins that are produced by cells in response to viral infections. They play a crucial role in the immune response by protecting other cells from viral replication. When a virus enters the body, interferons are released and bind to neighboring cells, signaling them to activate antiviral defenses. This activation interferes with the ability of the virus to replicate, thus preventing its spread to other cells. Therefore, the correct answer is that interferons protect other cells by interfering with the ability of a virus to replicate.

During meiosis, the diploid number of chromosomes is halved. In the first meiotic division, the number of chromosomes is reduced from 16 to 8. Then, in the second meiotic division, the sister chromatids are separated, resulting in four haploid cells. Therefore, at the end of telophase of the second meiotic division, each cell will have 8 chromosomes.

Epithelial layers are not penetrated by many blood vessels. Epithelial tissues are avascular, meaning they lack blood vessels. Instead, they receive nutrients and oxygen through diffusion from nearby blood vessels in connective tissues. This is important for maintaining the functionality and integrity of epithelial layers. Therefore, the statement that epithelial layers are penetrated by many blood vessels is false.

The matrix of connective tissue is not found inside the cell. Connective tissue is made up of cells and extracellular matrix. The matrix is a non-living component that surrounds and supports the cells. It consists of proteins, such as collagen and elastin, as well as ground substance, which provides a gel-like consistency. The matrix is secreted by the cells and exists outside of them, serving to connect and protect the cells within the tissue. Therefore, the statement that the matrix of connective tissue is found inside the cell is false.

A plasma cell is derived from a B-cell. B-cells are a type of white blood cell that are responsible for producing antibodies. When B-cells encounter an antigen, they differentiate into plasma cells, which secrete large amounts of antibodies to help fight off the infection. This process is an important part of the immune response and helps to eliminate pathogens from the body.

When the potassium gates open, it allows the movement of potassium ions out of the cell, causing the inside of the cell to become more negative or hyperpolarized. This hyperpolarization makes it more difficult for an action potential to be generated, reducing the excitability of the neuron. Therefore, the correct answer is hyperpolarized.

The given answer states that potassium diffuses out of the cell. This is because potassium gates open, allowing potassium ions to move from inside the cell to outside. This movement of potassium ions out of the cell helps to establish the resting membrane potential and plays a crucial role in maintaining cell function.

Healing by secondary intention involves the formation of granulation tissue to fill in the wound and promote healing. This process occurs when there is extensive tissue loss, which is not typical of healing by primary intention where the wound edges are closely approximated. Scarring is also a common outcome of healing by secondary intention. However, meiosis, the process of cell division that produces gametes, is unrelated to wound healing and does not occur in the context of secondary intention healing.

Receiving a vaccination stimulates the body's immune system to produce a response, leading to the production of antibodies and memory cells. This type of immunity is known as artificial active immunity because it is acquired through a deliberate action, such as receiving a vaccine, rather than naturally through exposure to a pathogen.

The thalamus is often referred to as the relay station for somatosensory information because it receives sensory signals from various parts of the body and then relays them to the appropriate areas of the cerebral cortex for further processing. It acts as a gateway, filtering and directing sensory information to ensure that only relevant signals reach the cortex. This helps in the perception and interpretation of touch, pain, temperature, and other somatosensory stimuli. The thalamus also plays a crucial role in regulating sleep and wakefulness, as well as controlling motor functions.

The statement is false because the action potential on neuron A does not split into four smaller action potentials prior to reaching neuron C. Action potentials are electrical signals that travel along the axon of a neuron, and they do not split or divide into multiple smaller signals. Instead, they propagate as a single, all-or-nothing event from the axon hillock to the axon terminals, where they can then transmit the signal to other neurons or target cells.

The correct answer is Sarcomere, Myosin. Sarcomere is the basic unit of muscle contraction and consists of overlapping actin and myosin filaments. Myosin is a protein that forms cross-bridges with actin during muscle contraction. Therefore, both sarcomere and myosin are directly related to muscle contraction and are the correct answers.

Plasma cells are responsible for producing antibodies. Antibodies, also known as immunoglobulins, are proteins that are produced by plasma cells in response to the presence of antigens. When an antigen enters the body, plasma cells recognize it and produce antibodies that bind to the antigen, marking it for destruction by other immune cells. Helper T-lymphocytes, cytotoxic T-cells, macrophages, and monocytes are all important components of the immune system, but they do not directly produce antibodies.

Recessive X-linked traits are more likely to be observed in males because they are inherited on the X chromosome. Males only have one X chromosome, so if they inherit a recessive trait on that chromosome, it will be expressed. Females, on the other hand, have two X chromosomes. If they inherit a recessive trait on one X chromosome, they have another X chromosome that may have a dominant allele to mask the recessive trait. Therefore, recessive X-linked traits are less likely to be expressed in females.

The A Band and H Zone are both components of a muscle sarcomere. The A Band is a dark band that contains overlapping actin and myosin filaments, while the H Zone is a lighter region within the A Band that contains only myosin filaments. Therefore, selecting A Band and H Zone as the correct answers makes sense in the context of muscle anatomy.

Antibody formation is a specific response to infection, as it involves the production of antibodies that specifically target and neutralize the invading pathogens. Phagocytosis, inflammation, interferon, and fever are all non-specific responses to infection, as they are general defense mechanisms that are activated in response to a wide range of pathogens.

The term "labile" refers to a cell type that is capable of dividing and regenerating quickly. Epithelial cells are known for their high turnover rate and ability to rapidly divide and replace damaged or lost cells. Neurons, osteoblasts, cardiac myocytes, and hepatocytes are not typically considered labile cell types. Therefore, the correct answer is epithelial.

If a woman who is not color blind but carries the allele for color blindness reproduces with a man who has normal color vision, there is no chance they will have a color blind daughter. This is because color blindness is a recessive trait that is carried on the X chromosome. Since the woman is not color blind, it means she has at least one normal X chromosome. The man also has normal color vision, so he has two normal X chromosomes. Therefore, all of their daughters will inherit at least one normal X chromosome from each parent, making them not color blind.

Artificial passive immunity is produced by an injection of antibodies that have been produced by another individual. In this type of immunity, ready-made antibodies are introduced into the body to provide immediate protection against a specific pathogen. This is different from natural active immunity, where the body produces its own antibodies in response to an infection or vaccination. Similarly, artificial active immunity is achieved through vaccination, where the body produces its own antibodies after exposure to a weakened or inactivated form of the pathogen. Natural passive immunity occurs when a baby receives antibodies from its mother through the placenta or breast milk. Therefore, the correct answer is artificial passive immunity.

Muscle spindles are the sensory receptors that participate in the knee jerk reflex. These specialized receptors are located within the muscle fibers and are responsible for detecting changes in muscle length and rate of change. When the knee is tapped, the muscle spindles are stimulated, sending sensory information to the spinal cord. This triggers a reflex response that causes the quadriceps muscle to contract, resulting in the knee jerk. Tendons, cutaneous receptors, and pressure receptors are not directly involved in the knee jerk reflex.

Chromatin is the material that makes up chromosomes. It consists of DNA molecules tightly coiled around proteins called histones. During cell division, the chromatin condenses and becomes visible as chromosomes. Each chromosome is made up of two identical sister chromatids, which are the result of DNA replication. Therefore, chromatin can be described as 1/2 of a double stranded chromosome because it represents one of the sister chromatids before they separate during cell division.

Cytokinesis is the process in which the cytoplasm of a cell divides to form two daughter cells. It typically begins during late anaphase, which is the stage of mitosis when the sister chromatids separate and move towards opposite poles of the cell. Cytokinesis then continues into telophase, which is the final stage of mitosis when the nuclear envelope reforms and the chromosomes decondense. Therefore, the correct answer is anaphase and telophase.

Interferons are proteins that are released by infected cells as a response to viral infections. They have antiviral properties and help to inhibit viral replication. Unlike the other options listed, interferons are not specific to a particular virus or pathogen. They are part of the innate immune response and are produced in response to any viral infection. Therefore, the production and secretion of interferon is a non-specific response to a viral infection.

If the anterior root of the spinal nerve is cut, it would result in a complete loss of movement in the regions supplied by that spinal nerve. The anterior root is responsible for carrying motor information from the spinal cord to the muscles, so if it is cut, the muscles will not receive any signals to contract, leading to a loss of movement. Sensation and autonomic control of blood vessels and sweat glands are not affected by cutting the anterior root, so they would still be intact.

The statement is true because even if the neurotransmitters secreted by neuron A are excitatory (EPSPs), there will not be enough EPSPs to produce an action potential on neuron C. This is because there is only one action potential on neuron A, and without the presence of neuron B, the EPSPs from neuron A alone will not be sufficient to trigger an action potential on neuron C.

The correct answer is IPSP. IPSP stands for inhibitory postsynaptic potential, which is a temporary hyperpolarization of the postsynaptic membrane caused by the opening of potassium channels or chloride channels. This inhibitory signal decreases the likelihood of an action potential being generated in the postsynaptic neuron, thus reducing neuronal activity. The other options mentioned, such as hyperpolarized, EPSP, and sodium gates open, are not directly related to IPSP.

The extrapyramidal pathway is responsible for maintaining muscle tone and posture. This pathway consists of various tracts that originate in the brainstem and project to the spinal cord. Unlike the corticospinal pathway, which is involved in voluntary movement, the extrapyramidal pathway controls involuntary movements and helps regulate muscle tone. The dorsal column pathway is responsible for transmitting sensory information related to touch and proprioception, while the spinothalamic pathway carries pain and temperature sensations. Therefore, the extrapyramidal pathway is the most appropriate answer for this question.

Membrane pumps are proteins that are located in the cell membrane. They possess ATPase activity, meaning they use ATP (adenosine triphosphate) to transport molecules across the membrane. These pumps can also be blocked by certain drugs, which can inhibit their function. This means that the drugs can prevent the pumps from transporting molecules across the membrane.

Connective tissue is a type of tissue in the body that connects, supports, and protects other tissues and organs. It is composed of many different types of cells, has a large amount of intercellular material called the extracellular matrix, and has a good blood supply. However, one characteristic that is NOT associated with connective tissue is cells arranged closely together. Connective tissue cells are typically scattered within the extracellular matrix, with varying degrees of spacing between them.

The correct answer is simple columnar. This type of epithelium is found in the lining of the stomach and intestine. Simple columnar epithelium is characterized by tall, elongated cells with nuclei located near the base of the cells. It provides protection and secretion, as well as absorption in the intestine. The tall shape of the cells allows for increased surface area, which is important for the absorption of nutrients in the intestine.

T-cells are a type of white blood cell that play a key role in the immune response. One of the functions of T-cells is to form memory cells, which are responsible for remembering specific pathogens that the body has encountered before. This allows the immune system to mount a faster and more effective response upon subsequent exposure to the same pathogen. Therefore, the correct answer is that T-cells form memory cells.

The correct answer is T and T System, Cross-Bridges. The T and T System refers to the transverse tubules, which are invaginations of the cell membrane in muscle fibers that help transmit electrical impulses for muscle contraction. Cross-Bridges, on the other hand, are the connections formed between the thick and thin filaments in a sarcomere during muscle contraction. Both T and T System and Cross-Bridges are important components involved in muscle contraction.

The normal latency of the knee jerk refers to the time it takes for the reflex to occur after the stimulus is applied. A latency of 35ms suggests that the reflex response is relatively quick, as it occurs within a short time frame. This indicates that the neural pathways responsible for the knee jerk reflex are functioning efficiently, allowing for a rapid response.

Fibrocartilage is the correct answer because it is the type of cartilage found in the spinal column. Fibrocartilage is a tough and dense connective tissue that provides support and absorbs shock in the spine. It is found in the intervertebral discs, which are located between the vertebrae in the spinal column. Fibrocartilage is characterized by its strong collagen fibers and ability to withstand compression, making it ideal for the spinal column's weight-bearing and protective functions.

The Z line is a structural protein that anchors the thin filaments in a sarcomere, while actin is a protein that makes up the thin filaments. Both of these components are important for the contraction of muscle fibers.

The correct answer is "Thin Filament" because in muscle contraction, the thin filament is responsible for sliding past the thick filament, causing the sarcomere to shorten and generate force. The thin filament is composed of actin, tropomyosin, and troponin, which work together to regulate muscle contraction. The other options listed (Cross-Bridges, T and T System, Sarcomere) are not directly related to the structure or function of the thin filament in muscle contraction.

When the potassium gates open, it allows the flow of potassium ions out of the neuron, leading to hyperpolarization. This hyperpolarization makes the neuron less likely to fire an action potential, resulting in an inhibitory postsynaptic potential (IPSP). On the other hand, when the sodium gates open, it allows the flow of sodium ions into the neuron, leading to depolarization and the generation of an excitatory postsynaptic potential (EPSP). Therefore, the correct answer is potassium gates open.

When sodium gates open, it allows sodium ions to enter the cell, leading to depolarization. This can result in the generation of an excitatory postsynaptic potential (EPSP), which is a small depolarization of the postsynaptic membrane. EPSPs can trigger an action potential and promote the firing of neurons. Therefore, the given answer suggests that when sodium gates open, it leads to the generation of an EPSP.

Exocrine glands are responsible for secreting substances, such as oils, onto the surface of the skin or into body cavities. These glands have ducts that transport the secretions to the desired location. Therefore, the correct answer is "exocrine" because it accurately describes the type of gland that secretes oils.

Epithelial cells can be categorized based on the number of layers they form in a tissue. A simple layer means that there is only one layer of epithelial cells, while a stratified layer means that there are multiple layers of epithelial cells.

The two sub-types of epithelium are covering, lining, and glandular. Epithelial tissues are classified based on their location and function in the body. Covering epithelium forms the outer layer of the skin and covers internal organs. Lining epithelium lines the cavities and tubes of the body, such as the digestive tract and blood vessels. Glandular epithelium is specialized for secretion and is found in glands throughout the body. These sub-types of epithelium serve different purposes and are adapted to their specific functions in the body.

Ciliated epithelial cells are found in the major airways of the respiratory system, such as the trachea and bronchi, where they help to move mucus and trapped particles out of the lungs. They are also found in the fallopian tubes of the female reproductive system, where their cilia help to move the egg from the ovary to the uterus.

The correct answer is stratified squamous cells. Stratified squamous epithelium is found in areas of the body that are subject to constant friction and abrasion, such as the mouth and the skin. This type of epithelium consists of multiple layers of flattened cells that provide protection against mechanical stress and injury. The outermost layer of cells continuously sheds and is replaced by new cells from the deeper layers, ensuring the maintenance of a healthy and intact barrier.