Digestive System Chapter 15. Tongue n Mostly muscle tissue –What type of muscle would it be? Frenulum – connects the tongue to the bottom of the mouth.
Post on 14-Dec-2015
216 Views
Preview:
Transcript
Digestive System
Chapter 15
Tongue Mostly muscle tissue
– What type of muscle would it be? Frenulum – connects the tongue to the
bottom of the mouth What is the purpose of the tongue? Papillae – rough projections that
contain taste buds– Why would these be rough?
Four types of taste buds – sweet, sour, salt, bitter
Palate 2 sections Hard Palate
– Also known as the maxilla– Anterior Portion
Soft Palate– Posterior Portion– This and the uvula are drawn up during
swallowing• Why is this important?
Blocks off the nasal passage during swallowing
Tonsils
Lingual – at the base of the tongue– Used as anchor, covered by lymphatic
tissue Palatine – Located on the side of the
tongue Which do you think is removed when
you have tonsillitis? Palatine – exposed to many pathogens
so they can easily become infected.
Teeth
2 sets Primary (baby) – 10 on each jaw
– What happens to these? They are lost
– The roots are resorbed and teeth are pushed out by secondary teeth
Secondary (permanent) – 16 on each jaw– Begin to appear around age six
Secondary Teeth Incisors – total of eight, front teeth
– Function? Tearing off bites Cuspids (Canine) – total of four,
sharper teeth (fangs)– Function?
Rip and Tear tough food.
Secondary Teeth
Bicuspids (premolar) – total of eight, behind cuspids, a bit flatter– Function?
Mash and grind, little bit of tearing Molars – total of 12, back teeth much
flatter (4 first, 4 Second, 4 Third)– Third also known as wisdom teeth– Function?
Mash and Grind Why do we need so many types of
teeth?
Tooth Structure Based on the name where do you think
each part is?– Crown –– Root –
Enamel – – Hardest substance in the body and cannot
be replaced– What problem does this pose?
Dentin – deep to the enamel and surrounds the pulp cavity (nutrient supply)
Salivary Glands
Main Secretions– Amylase – breaks down large starch
and glycogen molecules– Mucus –
• What is its purpose? Bind food particles and lubricate
alimentary canal What triggers secretions? Parasympathetic nervous system
Salivary Glands – 3 different glands
Paratid – Located anterior and inferior to the ear– Secretes saliva rich in amylase
Submandibular – Located where?– Secretes thicker saliva than paratid.
• Why thicker? Sublingual – Located where?
– Secretes primarily mucus
Pharynx
Connects nasal and oral cavities with the esophagus
Contains the epiglottis– What is this?
Flaplike structure used to seal off trachea during swallowing.
Has three sections- nasopharynx attaches nasal cavity- oropharynx attaches mouth- laryngopharynx attaches esophagus
Wall Structure
4 layers– Mucosa –
– Submucosa –
– Muscular layer -
– Serosa –
Esophagus
Connects pharynx to stomach– Function -
Ends at lower esophageal sphincter– What is a sphincter?– This one connects the stomach
and the esophagus, what will its function be?
Stomach
Location – Size is small when empty, yet it
can hold one liter. How? What happens in the stomach?
Stomach Regions of the stomach
• Cardiac - posterior to lower esophageal sphincter
– Function-
• Fundic – Most anterior portion– Function –
• Body – Main region– Function –
• Pyloric – most posterior region– Function –
Stomach ends at Pyloric Sphincter
Gastric Juice
4 Components Pepsin – Pepsinogen – Hydrochloric Acid –
• Mucus
Gastric Regulation
Produced regularly, but rate can vary What might cause it to vary?
Gastrin – What stimulates the release?
Gastric Mixing
How will the stomach perform its functions?
Chyme – Where does food go to exit stomach?
– How does the stomach move it there?
Pancreas
Located near posterior abdominal wall inferior to stomach
Secretes____ into the ___. Amylase Lipase Nuclease
What other important function?
Liver
Located… Lobed Multiple Functions
Blood –
Storage - Digestive functions
Metabolism of Carbohydrates, Lipids and Proteins Secretes ____ through the ___into the ____.
Bile
Consists of: 1.
Two types biliverdin and bilirubin
2. Only part of the bile that has digestive function Emulsification
3.
Storage area What does it store?
Reabsorbs water to concentrate __________.
Hormones stimulate sphincter to relax, open duct Causing what to happen?
Gallbladder
Questions If a person had a condition which limited their
ability to produce hydrochloric acid in the stomach, how might this affect digestion and why?
If someone lost control of their pyloric sphincter and was unable to contract it, how would this affect digestion?
Thinking about the contents of the stomach, what might happen to a person with a lower esophageal sphincter that does not contract completely?
top related