Monthly Quiz - Nov 2016

The main components of blood are platelets, red blood cells, plasma, and white blood cells. Platelets are responsible for blood clotting and preventing excessive bleeding. Red blood cells carry oxygen to the body's tissues and remove carbon dioxide. Plasma is the liquid portion of blood that carries nutrients, hormones, and waste products. White blood cells are part of the immune system and help fight off infections and diseases.

The pituitary gland produces hormones. This gland, located at the base of the brain, is often referred to as the "master gland" because it plays a crucial role in regulating various bodily functions. Hormones produced by the pituitary gland help control growth, metabolism, reproduction, and other essential processes in the body.

Prolactin (PRL) is the hormone responsible for milk production in a new mother. During pregnancy, the levels of prolactin increase, preparing the breasts for milk production. After childbirth, prolactin levels remain high, stimulating the production of milk by the mammary glands. This hormone is essential for the initiation and maintenance of lactation in postpartum women.

The somatic nervous system is responsible for controlling voluntary movements in the body, including the contraction and relaxation of skeletal muscles. This system allows us to consciously control and coordinate our movements, such as walking, running, and lifting objects. Heart rate, peristalsis (the movement of food through the digestive system), and respiration are all controlled by the autonomic nervous system, which regulates involuntary processes in the body.

The major nerve that passes from the level of the sacrum down the posterior leg is the sciatic nerve. This nerve is the longest and thickest nerve in the body and is responsible for providing motor and sensory innervation to the muscles of the posterior thigh, leg, and foot. It originates from the lower back and travels down the back of the thigh, branching out into smaller nerves to supply the lower leg and foot. The sciatic nerve is commonly associated with conditions such as sciatica, which causes pain, numbness, and tingling along its pathway.

The correct answer is "b and c" because the eyeball is moved by both the oculomotor nerve and the abducens nerve. The oculomotor nerve controls the movement of most of the eye muscles, including the muscles that move the eyeball up, down, and medially. The abducens nerve controls the lateral movement of the eye, allowing it to move outward. Therefore, both of these nerves play a role in moving the eyeball.

The extensor muscles are located on the posterior side of the forearm. These muscles are responsible for extending or straightening the wrist, fingers, and thumb. They work in opposition to the flexor muscles, which are located on the anterior side of the forearm and are responsible for flexing or bending the wrist and fingers. The extensor muscles play a crucial role in activities such as gripping, typing, and playing certain sports, where wrist and finger extension is required.

The endocrine system is responsible for regulating various body functions through the release of hormones. These functions include sexual development and function, metabolism and growth, and immune responses. However, urine production is not regulated by glands in the endocrine system. It is primarily controlled by the urinary system, specifically the kidneys, which filter waste products from the blood to produce urine.

A comminuted fracture is a type of fracture where the bone is crushed or shattered into multiple pieces. Unlike other types of fractures where the bone may be partially fractured or one end is driven into the other end, a comminuted fracture involves the bone being completely fragmented. This can occur due to high-impact injuries or severe trauma to the bone.

Erythropoietin is a hormone released by the kidneys that stimulates the production of red blood cells in the bone marrow. This hormone plays a crucial role in maintaining the body's oxygen-carrying capacity. When the kidneys detect low oxygen levels in the blood, they release erythropoietin, which then stimulates the bone marrow to produce more red blood cells. This helps to increase the oxygen-carrying capacity of the blood and ensure that the body's tissues receive an adequate supply of oxygen.

A compound fracture is a type of fracture where the broken bone pierces through the skin. This is a serious injury that requires immediate medical attention. The bone breaking through the skin increases the risk of infection and complicates the healing process.

Signals are passed through the nervous system both electrically and chemically. Electrically, signals are transmitted through the neurons in the form of electrical impulses called action potentials. These impulses travel along the neuron's axon, allowing the signal to be transmitted quickly over long distances. However, at the synapses between neurons, the signal is transmitted chemically. Neurotransmitters are released from the presynaptic neuron and bind to receptors on the postsynaptic neuron, allowing the signal to be transferred from one neuron to another. Therefore, both electrical and chemical processes are involved in the transmission of signals through the nervous system.

Meissner corpuscles are specialized nerve endings found in the skin that are responsible for detecting touch, pressure, and vibration. However, they are not involved in detecting temperature. Temperature sensation is detected by different types of receptors called thermoreceptors. These receptors are sensitive to changes in temperature and help us perceive hot and cold sensations. Therefore, Meissner corpuscles do not play a role in temperature detection.

Long bones are not adapted for protecting internal organs because they are primarily responsible for supporting body weight, absorbing stress, and facilitating movement. Protecting internal organs is the function of other skeletal structures, such as the ribs and the skull. Long bones, such as the femur and the humerus, have a cylindrical shape that provides strength and stability, allowing them to bear weight and withstand stress. They also have specialized ends that facilitate movement at joints. Therefore, protecting internal organs is not a function specifically adapted by long bones.

The patella, also known as the kneecap, is a small bone located in the front of the knee joint. It is a sesamoid bone, which means it is embedded within a tendon and acts to protect and increase the mechanical advantage of the tendon. Sesamoid bones are typically small and round, and they are found in locations where tendons pass over joints, such as the patella in the knee or the pisiform bone in the wrist.

Light passing through the lens is refracted and projected onto the retina. The lens is responsible for focusing the light onto the retina, which contains light-sensitive cells that convert the light into electrical signals that can be processed by the brain.

The carpals of the wrist are examples of short bones because they are small in size and cube-shaped. Short bones provide stability and support to the body, and their compact structure allows for limited movement. The carpals are located in the wrist joint and function to facilitate movement and provide flexibility to the hand.

Smooth muscle is responsible for many involuntary movements in the body, such as moving food along the digestive tract and generating peristalsis. It also forms part of the walls of the airways in the respiratory system, helping to regulate airflow. However, smooth muscle cannot contract voluntarily to move blood through the vasculature. This is because the movement of blood through the blood vessels is controlled by the involuntary contraction of the cardiac muscle in the heart, not smooth muscle.

Vibrations are transferred through the ear in the following order: First, the sound waves enter the ear and cause the tympanic membrane (eardrum) to vibrate. The vibrations from the tympanic membrane are then transferred to the malleus (hammer), which is connected to the eardrum. The malleus then transfers the vibrations to the incus (anvil), which is connected to the malleus. Finally, the incus transfers the vibrations to the stapes (stirrup), which is the smallest bone in the human body. The stapes then transmits the vibrations to the cochlea, which is the organ responsible for converting sound vibrations into electrical signals that can be interpreted by the brain.

The cerebellum is not part of the brainstem. The brainstem is made up of the medulla oblongata, pons, and midbrain. The cerebellum is a separate structure located at the back of the brain, below the occipital lobes. It is responsible for coordinating voluntary movements, balance, and posture, but it is not considered part of the brainstem.