3. Answer the following-
a. Write the functions of the tongue.
b. Explain the role played by different digestive juices in digestion and the organs which secrete
them.
c. What are villi?
d. Explain about the different kinds of the teeth and their functions in human beings.
Answers
Answer:
the tounge is vital for chewing swallowing food as well as for speech the four common tastes are sweet sour bitter and salty a fifth taste called umami results for tasting glutamate the tounge has many nerves that help detect and transmite taste signals to the brain
salivary glands
the main salivary glands are found In the cheeks under the tounge and around the jaw they secrete about 1qut saliva each day amylase also called ptyalene is an enzyme in saliva that breaks down starches or carbohydrates such as bread rice and potato lysozym is another enzyme which keeps mouth healthy saliva also contains mucus which coats the food and enables each bite to travel smoothly to digestive track
stomach
the stomach is an important organ digestion produce gastric juices which comprised of hydrochloric acid water and enzymes
pancreas
the pancreas is a leaf like organ which lie below the stomach
liver
the liver produces a greenish juice called bile which is stored and concentrated by the gall bladder
intestinal enzymes involves in breakdown of peptides sucrose lactose and maltose
the small intestine has million of small fingers projection called villi
there are four types of teeth
incisors the four front teeth in both the upper and lower jaws are called incisors the primary function is to cut food the two incisors on the either side of the midline are know as central incisors the two adjacent teeth to the central incisors are know as lateral incisors incisors have a single roots and a sharp incisal edge
canines there are four canines in the oral cavity two in the maxillary arch and two in the mandibular area they are behind and adjacent to the lateral incisors their function is to tear food they have a single pointed cusp and a single root they have the longest root of the teeth they also serve to form the corners of the mouth
premolars these teeths are located behind and adjacent to the canines and are designed to crush food there are eight premolars in the oral cavity there are two in each quadrant of the mouth the one closest to the midline is the first premolar and the one farthest from the middle is the second premolar these teeth can have three to four cusp the maxillary first premolar has two roots and the remaining premolars have a single root there are no premolar in the primary dentition
molars the most posterior teeth in the mouth are the molars they have broader and flatter surfaces with 4 to 5 cusp they are designed to grind food mandibular molars have typically two roots maxillary molars which are located behind the second molars have primary 3 roots there are 12 molars in the permanent dentition and three in each quadrant of the mouth they are named starting with closest to the midline as first molars second molars and third molars although some people do not fully develop the third molar third molars are often referred to as wisidom teeth the primary dentition only have eight molars