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For optimal chemical digestion, chyme must be delivered from the stomach slowly and in small amounts. This is because chyme from the stomach is typically hypertonic, and if large quantities were forced all at once into the small intestine, the resulting osmotic water loss from the blood into the intestinal lumen would result in potentially life-threatening low blood volume. In addition, continued digestion requires an upward adjustment of the low pH of stomach chyme, along with rigorous mixing of the chyme with bile and pancreatic juices. Both processes take time, so the pumping action of the pylorus must be carefully controlled to prevent the duodenum from being overwhelmed with chyme.

Disorders of the…

Small intestine: lactose intolerance

Lactose intolerance is a condition characterized by indigestion caused by dairy products. It occurs when the absorptive cells of the small intestine do not produce enough lactase, the enzyme that digests the milk sugar lactose. In most mammals, lactose intolerance increases with age. In contrast, some human populations, most notably Caucasians, are able to maintain the ability to produce lactase as adults.

In people with lactose intolerance, the lactose in chyme is not digested. Bacteria in the large intestine ferment the undigested lactose, a process that produces gas. In addition to gas, symptoms include abdominal cramps, bloating, and diarrhea. Symptom severity ranges from mild discomfort to severe pain; however, symptoms resolve once the lactose is eliminated in feces.

The hydrogen breath test is used to help diagnose lactose intolerance. Lactose-tolerant people have very little hydrogen in their breath. Those with lactose intolerance exhale hydrogen, which is one of the gases produced by the bacterial fermentation of lactose in the colon. After the hydrogen is absorbed from the intestine, it is transported through blood vessels into the lungs. There are a number of lactose-free dairy products available in grocery stores. In addition, dietary supplements are available. Taken with food, they provide lactase to help digest lactose.

The large intestine

The large intestine    is the terminal part of the alimentary canal. The primary function of this organ is to finish absorption of nutrients and water, synthesize certain vitamins, form feces, and eliminate feces from the body.

Structure

The large intestine runs from the appendix to the anus. It frames the small intestine on three sides. Despite its being about one-half as long as the small intestine, it is called large because it is more than twice the diameter of the small intestine, about 3 inches.

Subdivisions

The large intestine is subdivided into four main regions: the cecum, the colon, the rectum, and the anus. The ileocecal valve, located at the opening between the ileum and the large intestine, controls the flow of chyme from the small intestine to the large intestine.

Cecum

The first part of the large intestine is the cecum    , a sac-like structure that is suspended inferior to the ileocecal valve. It is about 6 cm (2.4 in) long, receives the contents of the ileum, and continues the absorption of water and salts. The appendix    (or vermiform appendix) is a winding tube that attaches to the cecum. Although the 7.6-cm (3-in) long appendix contains lymphoid tissue, suggesting an immunologic function, this organ is generally considered vestigial. However, at least one recent report postulates a survival advantage conferred by the appendix: In diarrheal illness, the appendix may serve as a bacterial reservoir to repopulate the enteric bacteria for those surviving the initial phases of the illness. Moreover, its twisted anatomy provides a haven for the accumulation and multiplication of enteric bacteria. The mesoappendix    , the mesentery of the appendix, tethers it to the mesentery of the ileum.

Questions & Answers

d. inversely proportional
John Reply
Airway resistance in the human lung is? a. Greatest in the generation of distal bronchioles in healthy people because these airways have the smallest radii b. Not increased during a forced expiration in a healthy subject c. Decreased when breathing through the mouth d. Inversely proportional
Maryam Reply
1. Chemical level 2. Cellular level 3.Tissue level 4. Organ level 5.Organ system level 5.Organismal level
Jamela Reply
d
HMD
High
HMD
why there is bleeding in menstruation?
KUHELI Reply
menopause
Vasu
no
KUHELI
no one ready to help me
Maryam
skin
The following hormones increase the blood glucose level except_____________? a. Parathormone b. Growth Hormone c. Epinephrine d. Thyroxine
Maryam
c.epinephrine
Divya
Which of the following is NOT a characteristic feature of alveoli in the lung? a. Poor blood supply b. A large surface area c. Thin walls d. Chemical layer called surfactant
Maryam
a.poor blood supply
Divya
poor blood supply
Tanvi
Excess of cortisol causes______________? a. Acromegaly b. Conn’s syndrome c. Diabetes insipidus d. Cushing syndrome
Maryam
plz fast
Maryam
cushing syndrome
Tanvi
thank you
Maryam
Airway resistance in the human lung is? a. Greatest in the generation of distal bronchioles in healthy people because these airways have the smallest radii b. Not increased during a forced expiration in a healthy subject c. Decreased when breathing through the mouth d. Inversely proportional
Maryam
name temporary endocrine gland in female.
KUHELI Reply
when does 1st meiotic division occur in male ?
KUHELI Reply
spermatogenesis
Vasu
) Which of the following best describes the human body's defense mechanism against environmental bacteria?
Homeostasis
Zeinab
What the answer plz
Zeinab
skin
KUHELI
Kuheli but I think skin is an organ not defence mechanism
Zeinab
Homeostasis is the system responsible for body response to external changes
Eliaz
skin
skin
Kharim
what is an inflammation
Lodrick Reply
it's a reaction from a body tissue
Perpenjeng
is the body own mechanism of fighting against disease especially infections or injuries.
Azapa
Inflammation is a tissue response to damage tissues
Zeinab
The following hormones increase the blood glucose level except_____________? a. Parathormone b. Growth Hormone c. Epinephrine d. Thyroxine
Maryam
which cells are responsible for bone formation?
Richard Reply
osteocytes
Sharon
Oestocytes
Zeinab
osteocytes
Vasu
The following hormones increase the blood glucose level except_____________? a. Parathormone b. Growth Hormone c. Epinephrine d. Thyroxine
Maryam
which muscles are innervated by the lateral plantar nerve?
Tinyiko Reply
what book should i read for my Msc exam (physiology)
zeleke Reply
let ask u aquiz where bones live in a body
Lowyer Reply
306 bones in a human body
Netope Reply
206 bones in a human body
Netope
there are 206 bones in human body and a baby's body has about 300 bones at birth
fatima
exactly
Abdimahadi
what is anatomy?
Nuwagaba Reply
anatomy is the study of the internal structure of a living organism
Favour
can be define as the Scientific Study Of internal structure of the body Some of this Structures are Very tiny they can only be seen by The assistance of a microscope, While other structures can be seen manipulated and Weighted
Abdurrahmal
Anatomy is the scientific study of the body and the physical relationship between systems
Cawuthara
Scientific study of body structure and function
Zeinab
study of body functions of living organisms and organs
Vasu
gross anatomy is the study of the internal structure of a living organism at a visible or macroscopic level
Favour Reply
homeostasis is the steady maintenance of the internal system
Favour
study of the structure of cells,tissue using a microscope
Favour
is the study of how the human body works and relates
Favour

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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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