Unit 9 Cow Eye Structure

12/15/22, 8:39 PM Unit 9 Cow Eye Structure Due: 11:59pm on Wednesday, December 14, 2022 Dissection Video Activity: Cow Eye (1 of 3) Watch the animation, then answer the questions. Part A Identify the fluid filled space between the cornea and iris. Hint 1. This area is filled with aqueous humor. ANSWER: Posterior segment Anterior chamber Anterior segment Posterior chamber Correct Correct. The anterior chamber is the fluid filled space between the cornea and iris. Part B 1/10 1/10 12/15/22, 8:39 PM Identify the structure that regulates the amount of light entering the posterior segment of the eye. Hint 1. This is a muscular structure. ANSWER: Cornea Lens Pupil Iris Correct Correct. The iris is a muscular structure composed of both circular and radially arranged smooth muscle cells. It is capable of changing the shape of the pupil, thereby adjusting the amount of light passing through the lens. Part C Identify the areas that are filled with aqueous humor. Hint 1. Aqueous humor is the watery fluid that fills the space in front of the lens. ANSWER: The posterior chamber and the posterior segment The anterior and posterior segments The anterior and posterior chambers The anterior chamber and the posterior segment Correct Correct. The anterior and posterior chambers make up the anterior segment, which is filled with aqueous humor. Part D The iris divides the eye into the anterior and posterior segments. Hint 1. 2/10 2/10 12/15/22, 8:39 PM The anterior segment is filled with aqueous humor. The posterior segment is filled with a gelatinous fluid called the vitreous body. ANSWER: True False Correct Correct. The lens divides the eye into the anterior segment, located in front of the lens, and the posterior segment, located behind the lens. Part E The pupil can adjust its size independent of the iris. Hint 1. The pupil conveys light to the lens. ANSWER: False True Correct Correct. The iris changes the diameter of the opening at its center, which is known as the pupil. Dissection Video Activity: Cow Eye (2 of 3) Watch the animation, then answer the questions. 3/10 3/10 12/15/22, 8:39 PM Part A Identify the parts of the fibrous layer. Hint 1. The eye is composed of 3 layers, the fibrous, vascular and neural layers. ANSWER: Cornea and iris Sclera and cornea Sclera and conjunctiva Cornea and lens Correct Correct. The fibrous layer consists of 2 parts: the sclera and cornea. Part B Identify the structure that allows light to first enter the eye. Hint 1. This structure belongs to the fibrous layer. ANSWER: 4/10 4/10 12/15/22, 8:39 PM Sclera Lens Pupil Cornea Correct Correct. The cornea is the transparent portion of the fibrous layer where light enters the eyeball into the anterior chamber before passing through the pupil to the lens. Part C Name the largest portion of the fibrous layer. Hint 1. The fibrous layer makes up the outer wall of the eye. ANSWER: Conjunctiva Sclera Choroid Cornea Correct Correct. The sclera makes up about 83% of the fibrous layer. Part D Which cranial nerve carries visual information from the eyeball to the brain? Hint 1. This nerve can be seen connected to the back of the eyeball. ANSWER: 5/10 5/10 12/15/22, 8:39 PM Oculomotor nerve Optic nerve Olfactory nerve Vestibulocochlear nerve Correct Correct. Cranial nerve II, the optic nerve, carries sensory information from the eyeball to the brain. Part E Only the fibrous layer can be observed in its entirety from the superficial surface of the cow eye. Hint 1. The eye is composed of 3 layers: the fibrous, vascular, and neural layers. ANSWER: True False Correct Correct. The vascular and neural layers are deep to the fibrous layer and can’t be observed from the superficial surface of the eye. Dissection Video Activity: Cow Eye (3 of 3) Watch the animation, then answer the questions. Part A 6/10 6/10 12/15/22, 8:39 PM Identify the muscular structure that anchors the lens in place. Hint 1. This structure surrounds the lens like a halo. ANSWER: Iris Suspensory ligaments Ciliary body Choroid Correct The ciliary body contains ciliary muscle that attachs the lens through the suspensory ligaments, anchoring it in place. Part B Where is the vitreous body located? Hint 1. The vitreous body is a thick gelatinous fluid filled sac. ANSWER: Anterior segment Posterior segment Anterior chamber Posterior chamber Correct Correct. The vitreous body is the thick fluid that fills the back of the eyeball behind the lens. Part C Identify the neural layer. Hint 1. 7/10 7/10 12/15/22, 8:39 PM The neural layer is found in the posterior segment. ANSWER: Choroid Retina Optic nerve Sclera Correct Correct. The retina is the neural layer that senses incoming visual information and sends that sensory input to the brain through the optic nerve. Part D Which of the following structures is highly vascular? Hint 1. Nutrients from this layer diffuse into adjacent avascular layers. ANSWER: Choroid Cornea Retina Sclera Correct Correct. The choroid is the vascular layer. It is a membrane with a rich blood supply which nourishes the eye. It’s dense blood supply gives the choroid a very dark color. Part E Which of the following regions is known as the blind spot? Hint 1. The blind spot is region on the retina. ANSWER: 8/10 8/10 12/15/22, 8:39 PM Macula lutea Fovea centralis Ciliary body Optic disc Correct Correct. The optic disc is where the optic nerve exits the eye. Photoreceptor cells are not present in this region, and therefore visual information can not be received in this area. Part F Identify the incorrect statement regarding the vitreous body. Hint 1. The vitreous body fills the posterior segment. ANSWER: Supports the posterior surface of the lens Holds the retina against the choroid Consists of a thin, watery fluid Transmits light Correct Correct. The vitreous body is the gelatinous fluid that fills the posterior segment. The aqueous humor found in the anterior segment is a thin watery fluid. Exercise 23 Post-Lab Question 6 Part A This structure, present in the cow eye but not in the human eye, is a special iridescent reflecting surface that helps animals to see in low light conditions. ANSWER: 9/10 9/10 12/15/22, 8:39 PM ciliary body vascular layer pigmented sclera tapetum lucidum Correct Score Summary: Your score on this assignment is 91.9%. You received 91.94 out of a possible total of 100 points. 10/10 10/10