Download Digestive

BIOL 2030 Human Anatomy & Physiology II
Why do we have a digestive system?
Provide nutrients to all tissues in the body
What tasks does your
digestive system do?
Ingestion, mastication,
propulsion, mixing, secretion,
digestion, absorption,
transportation, elimination
What is digestion?
Breakdown of organic molecules/nutrients... mechanical
and chemical
See Table 24.1
What happens between my mouth and anus?
Organ
Oral cavity
Pharynx
Function
Time
ingestion/mastication
10-20 sec.
secretion/mixing/digestion
transportation
1-2 sec.
Esophagus
transportation/propulsion 5-8 sec.
Stomach
digestion/secretion
3-4 hrs.
mixing
digestion/secretion/mixing 3-5 hrs.
absorption/propulsion
Small intestines
Pancreas
Liver
Large intestines
Rectum
Anus
absorption/propulsion
elimination
18-36 hrs.
What structures exist between mouth and anus?
Graphic
overview of
alimentary
canal
What is the oral cavity and what does it do?
Graphic
overview of
…
What is the oral cavity and what does it do?
Vestibule: space
between cheeks, lips
and gums
Oral cavity proper:
space within floor of
mouth and roof (palate)
Ingestion
(alternate routes)
Mastication = chewing
Which type of digestion? Why?
Accomplished via: cheeks, lips,
tongue, teeth, jaws
permanent
deciduous
Types of teeth:
Incisors
Canines
Premolars
Molars
How do you masticate?
Teeth embedded in:
Alveoli in the Maxilla
(upper jaw) &
Mandible (lower jaw)
Closing jaw =
masseter
temporalis
medial pterygoids
Opening jaw =
lateral pterygoids
How do you salivate?
3 paired glands:
Parotid
Submandibular
Sublingual
Scattered small
tubular glands
Secrete mucus, serous fluid
and enzymes
Endocrine or Exocrine?
What can your palate do for you ?
Hard and Soft palates
Cleft lip/palate:
congenital defect where
embryonic tissues fail to
fuse
“Because I was different”
by Don Bartlette
How does food get from oral cavity to esophagus?
Food formed into a bolus
Which of the
Pushed against hard palate by tongue pharynxes usually
conduct food?
Initiates swallowing reflex
Pharyngeal muscles aid in pushing
into esophagus
Swallowing (deglutition) divided
into 3 phases:
1) voluntary
2) pharyngeal
3) esophageal
What is the role of the esophagus?
Conducting Tube
~ 12” in length
2 sphincters:
upper
esophageal
lower esophageal
or cardiac
Generalized
layers of
alimentary canal
1
2
3
4
What is the role of the enteric plexus?
Nerve plexus
allows local
reflexes to be
integrated
independent of
the CNS.
Sensory neurons
Motor neurons
1
2
Interneurons
3
4