Unit IV: Neuron Classification, Reflexes & Vision

The correct answer is "lens, lens" because the question asks to identify "C" and the only word mentioned in the question is "lens." The repetition of "lens" in the answer suggests that it is the correct identification for "C."

The correct answer is "cornea." The word "cornea" is repeated twice in the question, suggesting that it is the correct identification for B. The repetition of the word reinforces the idea that B is indeed the cornea.

The correct answer is Optic Disc. The term "G" refers to the optic disc, which is a small, circular area in the retina where the optic nerve exits the eye. It is also known as the blind spot because it lacks photoreceptor cells, making it insensitive to light. The options "Blind Spot," "Blind spot," and "blind spot" all refer to the same concept, while the options "Optic Disc" and "Optic disc" provide the correct scientific term for G.

The structure at the pointer is a sensory neuron. The term "sensory neuron" refers to a type of nerve cell that transmits sensory information from the peripheral nervous system to the central nervous system. The correct answer is "Sensory Neuron" as it is the proper noun form, while "Sensory neuron" and "sensory neuron" are just variations in capitalization.

The spinal cord is indeed part of the central nervous system (CNS). The CNS consists of the brain and spinal cord, which work together to process and transmit information throughout the body. The spinal cord is a long, thin bundle of nerves that extends from the brain down the back. It is responsible for relaying messages between the brain and the rest of the body, allowing for the coordination of movement and the transmission of sensory information. Therefore, it is accurate to say that the spinal cord is part of the CNS.

The correct answer is "lacrimal gland" because it is the name of the structure being identified. The repetition of the term in different capitalization formats suggests that it is the correct answer. The lacrimal gland is responsible for producing tears, which help keep the eyes lubricated and protect them from foreign particles.

The correct answer is any of the given options: Fovea Centralis, Fovea centralis, fovea centralis, fovea, Fovea. These options all refer to the same anatomical structure in the eye known as the fovea centralis. The fovea centralis is a small, central pit in the retina that contains a high concentration of cone cells, which are responsible for high visual acuity and color vision. It is the area of the retina that provides the sharpest vision and is responsible for detailed tasks such as reading and recognizing faces.

The correct answer is "Posterior Segment, Posterior segment, posterior segment". The question asks to identify "H," and the given options all refer to the posterior segment. This suggests that "H" is also referring to the posterior segment.

The correct sequence of a reflex arc is as follows: receptor, sensory neuron, integration center/control center, motor neuron, and effector organ. This sequence describes the pathway that a reflex signal follows in the body. The receptor detects a stimulus, which is then transmitted to the sensory neuron. The sensory neuron carries the signal to the integration center/control center, where it is processed. The processed signal is then transmitted to the motor neuron, which in turn sends the signal to the effector organ, causing a response. Therefore, the given statement is true.

The nasolacrimal duct is a passage that connects the lacrimal sac to the nasal cavity. Tears produced by the lacrimal gland drain into the lacrimal sac and then travel through the nasolacrimal duct to the nasal cavity. This is why when we cry, our nose gets runny. So, the statement "E is the nasolacrimal duct" is true.

The correct answer is "Effector organ, Effector Organ, effector organ." This answer suggests that the structure at the pointer is an effector organ. The repetition of the term with different capitalization indicates that it is referring to the same structure, regardless of the case sensitivity.

The substance in the anterior segment of the eye is known as aqueous fluid. This is true because the anterior segment of the eye contains a clear, watery fluid called aqueous humor. Aqueous humor is produced by the ciliary body and fills the space between the cornea and the lens. It helps maintain the shape of the eye, provides nutrients to the cornea and lens, and helps to regulate intraocular pressure.

The choroid is a layer of tissue in the eye that contains blood vessels. These blood vessels supply oxygen and nutrients to the retina, which is responsible for capturing light and sending visual signals to the brain. Therefore, the statement that the choroid helps capture light in the eye is true.

Bipolar neurons are indeed the most rare neurons in the human body. Unlike other neurons that have multiple dendrites and a single axon, bipolar neurons have only two processes, one dendrite, and one axon. They are found in specialized sensory organs like the retina of the eye and the olfactory epithelium in the nose. These neurons play a crucial role in relaying sensory information from these organs to the central nervous system. Due to their limited presence and specialized function, bipolar neurons are considered to be the rarest type of neurons in the human body.

None of these detect black and white light because black and white vision is primarily detected by rods, not cones. Cones are responsible for color vision, while the choroid is a layer of tissue in the eye that provides nourishment to the retina. The lens focuses light onto the retina, but it does not specifically detect black and white light.

The fovea centralis is the part of the eye that contains the highest concentration of photoreceptors, specifically cone cells. These cone cells are responsible for color vision and high visual acuity. The fovea centralis is located in the center of the macula, which is the central part of the retina. It is the area of the eye that is responsible for sharp, detailed vision, making it the correct answer in this case.

The innermost tunic of the eye is not the choroid. The correct answer is false. The innermost tunic of the eye is the retina, which contains the light-sensitive cells that convert light into electrical signals for the brain to process. The choroid is a layer located between the retina and the outer sclera of the eye, and it provides oxygen and nutrients to the retina.

The correct answer is Sclera. The fibrous tunic of the eye is made up of the sclera, which is the white, tough, and fibrous outer layer of the eye. It provides structural support and protection to the eye. The cornea is a transparent layer at the front of the eye, while the ora serrata is a jagged boundary between the retina and the ciliary body. Therefore, neither the cornea nor the ora serrata make up the majority of the fibrous tunic.

The fibrous tunic is the outermost layer of the eye. It consists of the cornea and sclera, which provide protection and maintain the shape of the eye. The ora serrata, on the other hand, is part of the vascular tunic, also known as the uvea, which is the middle layer of the eye. It marks the transition between the retina and the ciliary body. Therefore, the ora serrata is not part of the fibrous tunic.

A neuron being structurally multipolar does not necessarily mean it is sensory in function. The classification of a neuron's function is based on its role in transmitting and processing information, not its structure. Neurons can have different structural types (such as multipolar, bipolar, or unipolar) and still have various functions, including sensory, motor, or interneuron functions. Therefore, the statement that a structurally multipolar neuron is always sensory in function is false.