Human Digestive System Flashcards
Define human alimentary canal
Its a long tract/tube which connects with the external environment and can fulfill the steps of holozoic mode of nutrition
What does the human digestive system consist of
Alimentary canal
Associated glands
Components of alimentary canal
- Mouth/Oral cavity
- Pharynx
- Esophagus
- Stomach
- Small intestine
- Large intestine
- Rectum
- Anus
Associated glands include
- Salivary glands
- Liver
- Pancreas
Describe oral cavity
- Oral cavity consists of tongue, teeth and salivary glands
- Ingestion and initial steps of digestion are carried out in oral cavity
- Both mechanical and chemical digestion takes place in the mouth
Components of oral cavity
tongue
teeth
salivary glands
Whats carried out in oral cavity
- Ingestion and initial steps of digestion are carried out in oral cavity
- Both mechanical and chemical digestion takes place in the mouth
Describe teeth
- There are 4 teeth types: incisors, canines, premolars and molars
- Functions:
1. Food is cut, mashed and ground by different teeth types with different shapes
2. Makes it easier to swallow food
3. Increases surface area for digestion
Functions of teeth
- Food is cut, mashed and ground by different teeth types with different shapes
- Makes it easier to swallow food
- Increases surface area for digestion
Describe salivary glands
- Salivary glands release saliva into oral cavity through ducts
- Releasing saliva into the oral cavity occurs when food enters the oral cavity due to a nervous reflex
- Saliva is also released into the mouth before food digestion due to various other stimuli (ex: sight, odor of food)
- Saliva contains water, amylase, mucin (a viscous mixture of salts, cells and slippery glycoproteins called mucins), buffers and anti-microbial components
what does saliva contain
water
amylase
mucus (a viscous mixture of salts, cells and slippery glycoproteins called mucins), buffers
anti-microbial components
what is mucus
a viscous mixture of salts, cells and slippery glycoproteins called mucins
how is saliva released to oral cavity
through ducts
what are the 2 instances saliva is released into oral cavity
- Releasing saliva into the oral cavity occurs when food enters the oral cavity due to a nervous reflex
- Saliva is also released into the mouth before food digestion due to various other stimuli (ex: sight, odor of food)
what are the stimuli that stimulate saliva release into mouth
sight
odor of food
functions of saliva
- Salivary amylase
Chemical digestion of polysaccharides (starch) into smaller polysaccharides and disaccharides into maltose
- Water
Liquifies food
Provides a watery medium for chemical digestion
Aids in taste reception
- Mucus
Lubricates food to make it easier to swallow
Cleans mouth
Protects mouth lining from abrasion
- Antimicrobial components (lysozymes, immunoglobulin)
Protect against bacteria that enter the mouth
- Buffers
Prevents tooth decay by neutralizing acid
buffers function
Prevents tooth decay by neutralizing acid
antimicrobial components function
Protect against bacteria that enter the mouth
mucus functions
Lubricates food to make it easier to swallow
Cleans mouth
Protects mouth lining from abrasion
salivary amylase function
Chemical digestion of polysaccharides (starch) into smaller polysaccharides and disaccharides into maltose
water functions
Liquifies food
Provides a watery medium for chemical digestion
Aids in taste reception
Give examples for antimicrobial components in saliva
lysozymes
immunoglobulin
Describe tongue
- composed of skeletal muscles
- Functions:
- Helps mix food with saliva and make food bolus that makes swallowing easier
- Then helps push bolus into the posterior part of oral cavity into the pharynx
composition of tongue
skeletal muscles
functions of tongue
- Helps mix food with saliva and make food bolus that makes swallowing easier
- Then helps push bolus into the posterior part of oral cavity into the pharynx
describe pharynx
- A common passage of the respiratory tract and digestive tract
- The pharynx leads to esophagus
what is pharynx the common passage of
respiratory and digestive tracts
what does pharynx lead to
esophagus
describe esophagus
- it’s a long tube connecting pharynx and stomach
- It’s found in thoracic cavity
- The wall of esophagus contains both skeletal and smooth muscles
- The skeletal muscles are located towards the uppermost part of esophagus and these muscles function in swallowing
- The rest of the esophagus contains smooth muscles involved in a process called
peristalsis - Peristalsis is a process where food bolus is pushed along the esophagus, which is an alternative wave of rhythmic contractions and relaxations of the smooth muscles lining the esophagus
where is esophagus found
thoracic cavity
what does esophagus connect
pharynx and stomach
what does the esophagus wall contain
smooth and skeletal muscles
where are the skeletal muscles of esophagus found
towards the uppermost part of esophagus
what do skeletal muscles in esophagus function in
swallowing
what do smooth muscles in esophagus function in
peristalsis
define peristalsis
Peristalsis is a process where food bolus is pushed along the esophagus, which is an alternative wave of rhythmic contractions and relaxations of the smooth muscles lining the esophagus
