Answer:
The <u>Orbicularis oris</u><u> </u>causes the lips to close and pucker during kissing, whistling and speaking.
Explanation:
<u>Orbicularis oris muscles are facial muscles which are located in the thickness of lip around oral opening. </u>
The muscle consists of two main parts
(a) Marginal part consisting of the longitudinal fibers -Closes the oral opening.
(b)Labial part consisting of the circular fibers - pushes the lips forward.
The main function of the orbicularis oris is closing of the mouth. It puckers the lips when it contracts.
These muscles are used to do actions like kissing, whistling and speaking.
Thus,
The <u>Orbicularis oris </u>causes the lips to close and pucker during kissing, whistling and speaking.
Answer:
“dorsal and ventral” are most commonly used. In the human, objects near the front are "anterior"; those near the rear are "posterior" – in the quadruped, these correspond respectively to "ventral" and "dorsal". On the limbs, an object closer to the main body is "proximal"; an object farther away is "distal"
Explanation:
Answer:
b. osteoclasts
Explanation:
Osteoclasts are large multi nucleated cells. They are found in pits of the bone surface. They have many vesicles and vacuoles leading to a "foamy" cytoplasm. They also have lysosomes filled with acid phosphatase.
Osteoclasts' primary function is to breakdown bone tissue that is required for repair, maintenance and remodeling of bones. They digest the bone by secreting collagenase and acid in a process called as bone resorption. Bone resportion as a pathological response is called as osteolysis. It can be caused by inflammation, tumor and cyst.
Answer:
c. synaptic cleft
Explanation:
A neuromuscular junction is formed between a motor neuron and a muscle fiber called as sarcolemma. A signal is passed from motor neuron to muscle fiber which eventually leads to muscle contraction.
Motor neurons release the neurotransmitter Acetylcholine in synaptic cleft. Acetylcholine diffuses through it and ultimately binds to the nicotinic acetylcholine receptors on cell membrane of sarcolemma. Nicotinic acetylcholine receptors are ligand gated ion channels and get depolarized by binding to acetylcholine which results in muscle contraction.