The Human Digestive System Flashcards
[___] involves the taking in of food and drink substances through the mouth.
Ingestion
[___] digestion involves the physical breakdown of large food particles into smaller ones without chemically altering the food particles. E.g. cutting, chewing, grinding and churning.
❥ [___] digestion involves the chemical breakdown of food molecules into smaller, more water-soluble ones by the action of digestive enzymes.
❥ Mechanical digestion aids chemical digestion by breaking food into smaller pieces, which are more easily accessible by [___ ___].
❥ Chewing, grinding and churning of food are examples of [___ ___]
❥ [___] digestion is carried out by the [__].
❥ The breakdown of food by enzymes is [___ ___].
Mechanical ❥ Chemical ❥ digestive enzymes ❥ mechanical digestion ❥ Mechanical - teeth ❥ chemical digestion
[___] is the process during which the small, water-soluble molecules and ions produced by digestion pass into the bloodstream, which transports them to different body organs. Absorption mostly occurs in the [__ __].
Absorption - small intestine
[___] is the uptake of nutrients (e.g. glucose and amino acids) from the bloodstream by body cells where they are subsequently used.
Assimilation
[___] is the process of expelling out of the body through the anus, the food molecules that are not [___] and absorbed, in the form of feces. The undigested food consists of the [____] that cannot be digested in our bodies.
Egestion - digested - fiber/roughage
Teeth are embedded in sockets in the jawbones. These sockets are tightly sealed by a soft tissue (like a collar) called the [__].
❥ Gums can act as [__ ___]. They protect the underlying bone from damage during chewing.
❥ Gums also form a barrier against [___] of underlying tissues.
gum
❥shock absorbent
❥infection
The visible part of the tooth that projects into the oral cavity is called the [___].
crown
The crown of the tooth is covered by the [___]: the white to off-white, non-living substance that offers a surface for the processing of food by the teeth inside the mouth. The enamel is highly [___]. It is the hardest substance made by the human body, and it does not break or get chipped easily. However, it is sensitive to [__] which can cause its demineralization.
enamel - mineralized - acids
The [__] is a living part of the tooth that contains strands of cytoplasm. It is provided with oxygen and nutrients by the [__ __].
dentine - pulp cavity
The pulp cavity is located in the [__] of the tooth, within the [___].
❥ The pulp cavity contains [__ __] and [__ __].
❥ The blood capillaries provide [__ _ __] to the surrounding dentine and keep it
alive.
❥ The nerve endings help the tooth to detect [___] e.g. pain.
center - dentine
❥ blood capillaries - nerve endings
❥ O2 and nutrients
❥ stimulus
The part of the tooth that is embedded in the gum is called the [__].
root
The root is not covered by enamel, instead, a thin layer of hard mineralized tissue called
[__] surrounds the [__].
cement - root
[___] containing protein fibers extend from the cement to the jawbone to anchor the tooth in its socket. These [__] but strong [__] allow the tooth to slightly move while chewing or biting.
Ligaments - flexible - fibers
Description of incisors of humans:
❥ Incisors are [__ __]; they are found at the [__] of the mouth.
❥ They are used for [__ _ __] pieces of food.
❥ Humans have [_] incisors: 4 in the upper jaw and 4 in the lower jaw.
❥ Incisors have [__] roots.
❥ chisel-shaped - front
❥ biting and cutting
❥ 8
❥ single
Description of canines of humans:
❥ Canine teeth are found directly next to the [__], at each of their sides.
❥ They are more [__] than the incisors.
❥ Like incisors, they are used for [__] and [__] pieces of food.
❥ Humans have [_] canines in their milk teeth and permanent teeth.
❥ Canines have [__] roots.
❥ incisor ❥ pointed ❥ biting - cutting ❥ 4 ❥ single
Description of premolars of humans:
❥ Premolars have a [__] surface for processing food than incisors and canines.
❥ Premolars are located directly [__] the canine tooth.
❥ Each premolar has two or more elevated tips called [__], which are used for
[__ _ __] food.
❥ Humans have [_] premolars: 4 in the upper jaw and 4 in the lower jaw.
❥ Most premolars have a [__] root but some have two roots.
❥ broader ❥ behind ❥ cusps - crushing and grinding ❥ 8 ❥ single
Description of molars of humans:
❥ Molars are found [______], behind the premolars.
❥ Molars are similar to premolars but are slightly [__], with [__ _ __] cusps each.
❥ Molars are also used for [__ _ __] food.
❥ Adult humans have [_] molars in total: 6 in the upper jaw and 6 in the lower jaw.
❥ Molars have [__ _ __] roots.
❥ at the back of the jaw ❥ larger - four or five ❥ crushing and grinding ❥ 12 ❥ two or three
[__] in the mouth combines with saliva and food forming a sticky layer that covers the teeth’s gums called [__].
❥ After a meal, food containing [__] is left behind in the teeth.
❥ The bacteria feed on sugar, then respire anaerobically changing the sugar into
[__ __].
❥ The lactic acid dissolves the [__] in the hard [__] and causes [__ __] which is manifested by the appearance of [__] in the tooth.
❥ Tooth decay may spread deep into the tooth if not managed properly and can grow larger as the lactic acid dissolves the softer [__].
❥ A dentist can clean and fill the cavities if they are discovered at [__ __]. If not the bacterial infection might reach advantages stages such as spreading to the [__ __] where nerve endings are present, causing a [___].
❥ The infection can cause an [__] or a collection of pus in the tissues accompanied by swelling, redness and pain at the root of the tooth.
❥ When the infection reaches the [__] of the tooth, the tooth will have to be taken out.
Bacteria - plaque ❥ sugar ❥ lactic acid ❥ calcium - enamel - tooth decay - cavities ❥ dentine ❥ early stages - pulp cavity - toothache ❥ abscess ❥ root
When bacteria combine with sugars from food stuck in the teeth, saliva, and other components, a sticky layer called [__] is formed over the gums and teeth.
❥ A collection of pus in the tissue accompanied by [__], [__], and pain at the root of the tooth is called an [__].
❥ The inflammation of gums that become swollen, tender, and may bleed during brushing is known as [___].
❥ If plaque remains stuck on the teeth it can harden and form [__].
plaque
❥ swelling - redness - abscess
❥ gingivitis
❥ tartar
The alimentary canal also called the [__ __] or gut is a long tube running through the body from the mouth to the anus.
❥ The main organs that make up the alimentary canal are the [__], [___], [__], [__ __] and [__ __].
❥ The accessory organs of the digestive system include: the [__], [__ __], [__] and [__ __].
digestive tract
❥ mouth - esophagus - stomach - small intestine - large intestine
❥ pancreas - gall bladder - liver - salivary glands
Saliva is an [__] digestive juice in the mouth produced by the [__ __].
❥ Saliva is a mixture of [__], [__], and [___].
❥ [__] in saliva provides the medium needed to dissolve food molecules, which
can then stimulate taste receptors.
❥ Saliva contains [__] which allows food particles to stick together forming a soft lubricated ball-like mixture known as a [__] that can be easily swallowed.
❥ The enzyme [__ __] starts the digestion of the starch found in the ingested food, breaking it down into a soluble disaccharide sugar called [__]. The digestion of starch is continued in the small intestine.
alkaline - salivary glands ❥ water - mucus - enzymes ❥ Water ❥ mucus - bolus ❥ salivary amylase - maltose
Digestion of carbohydrates begins in the [__], when starch is hydrolyzed into [__] by [__ __].
mouth - maltose - salivary amylase
