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What is the shape of the lens controlled by?
the iris!!! iris is the coloured part of your eye,and its a muscle that controls your pupil(the black dot) to let how much light you're eye needs. The iris regulates the amount of light by controlling the size of the pupil.
Is the ciliary muscle relaxed during distance vision?
Yes, the ciliary muscle is relaxed for distant vision, but is contracted for close vision.
What is the parasympathetic ganglion that serves the eye?
the effects are ciliary muscle contraction leading to a constricted pupil and opening of the canal of schlemm to all aqueous humour drainage. Also there is an increase in tear formation. The PNS has a role in accomodation to light.
What term describes the structure that holds the lens of the eye in place?
Ciliary Muscle
What is the object pulled on by ciliary muscles to bend the light?
The object pulled on by ciliary muscles to bend light is the lens of the eye. The ciliary muscles change the shape of the lens, which allows the eye to focus on objects at different distances.
What does the ciliary muscle of the eye control?
The ciliary muscles are sphincter muscle that controls the thickness of the lens. Each eye has a ciliary muscle around the lens of the eye. When the muscle contracts the lens gets compressed, and therefore thicker, meaning that it refracts light more (and shortens the focal distance). When it relaxes the reverse is true. They are innervated by parasympathetic fibres originating in the occulomotor nucelus of the midbrain which travel (along with somatic fibres to the extrinsic muscles of the eye) along the occulomotor nerve (cranial nerve III). okkk
How does MLCK activate myosin?
Myosin Light Chain Kinase (MLCK) activates myosin by phosphorylating the regulatory light chains of myosin II, which is crucial for muscle contraction. When calcium ions bind to calmodulin, this complex activates MLCK. The phosphorylated myosin then interacts with actin filaments, leading to muscle contraction through the sliding filament mechanism. This process is essential in various physiological functions, including smooth muscle contraction and cell motility.
What two involuntary muscles make up the front part of the eye?
The two involuntary muscles that make up the front part of the eye are the iris and the ciliary body. The iris controls the size of the pupil, regulating the amount of light entering the eye. The ciliary body adjusts the shape of the lens, enabling the eye to focus on near or distant objects.
What are the differences between the a and i bands in terms of their function and structure?
The A band is the dark band in a sarcomere that contains thick myosin filaments and does not change length during muscle contraction. The I band is the light band that contains thin actin filaments and shortens during muscle contraction. The A band provides stability and structure, while the I band allows for muscle contraction and relaxation.
The suspensory ligament is what during distance vision?
During distant vision, the ciliary muscle is relaxed, the suspensory ligament is taut, the convexity of the lens is increased, and light refraction is decreased. During close vision, the ciliary muscle is contracted, the suspensory ligament is relaxed, lens convexity is increased, and light refraction is increased.
What do the light and dark banding pattern seen in striated muscle originate from?
The light and dark banding pattern in striated muscle, known as striations, originates from the arrangement of myofilaments within the muscle fibers. The dark bands, or A bands, are composed of thick filaments (myosin) and overlap with thin filaments (actin), while the light bands, or I bands, consist only of thin filaments. This alternating pattern results from the structural organization of the sarcomeres, the functional units of muscle contraction, and allows for efficient muscle contraction and force generation.
What is the unit of alternating light and dark striations between z lines?
The unit of alternating light and dark striations between Z lines in a muscle fiber is called a sarcomere. Sarcomeres are the functional units of muscle responsible for muscle contraction and relaxation.
