Immune, Digestive, Respiratory, and Circulatory Systems Test (5/22/15) Flashcards
what is the purpose of the digestive system?
to break the things you eat down into nutrients
mechanical digestion
- usually some kind of physical force
- puts food into smaller form, allowing the enzymes of chemical digestion to be more effective
chemical digestion
- involves enzymes (protein molecules)
- allows you to break things down
absorption
transporting nutrients from your digestive system into the blood
propulsion
- the organ moves the food along to the next place
- most of this occurs with smooth muscle under voluntary control
mouth
-food is ingested here
• Mechanical and chemical digestion
o Mechanical: teeth and tongue
o Chemical:
• Carbohydrates begin to be digested
• When you chew, saliva concentration increases, enzymes are found in saliva. The name of the specific enzyme in your saliva is amylase.
• Saliva moistens food. This makes it easier to swallow.
o Saliva also helps to rinse your teeth.
o It contains an antibacterial agent that makes it harder for bacteria to grow in your mouth
o Dissolves food, allowing your taste buds to detect it
• As a result of digestion in the mouth, food is called the bolus
• No absorption
• Propulsion (when you swallow/swallowing reflex)
pharynx
• A small space in the back of your mouth
• The respiratory and digestive systems meet
o The respiratory pathway directs air to your lungs
o The bolus needs to go down the esophagus, not the respiratory tract
• The body prevents this from happening with a flap of muscular tissue known as the epiglottis. When you swallow, the flap closes over the respiratory passage.
• No digestion
• No absorption
• No propulsion
esophagus
The function is to lead the bolus from the pharynx down into the stomach.
• No digestion
• No absorption
• Propulsion does occur
o Peristalsis
• As one part contracts, the other part relaxes, squeezing the bolus down farther and farther towards the stomach.
• Alternating waves of muscle contraction.
stomach
• Chemical digestion
o Proteins begin to be digested
o The enzyme that digests proteins is called pepsin.
o The stomach also releases HCL (hydrochloric acid). This activates enzymes to start digestion. Otherwise, the stomach would digest its own walls.
o The stomach has a pH of 2, so it is a very strong acid
• To protect itself, the stomach has a thick lining and a lot of mucus.
• People develop ulcers when mucus isn’t as thick as it should be, allowing the walls of the stomach to burn
• Mechanical digestion:
o A little bit of this occurs with the churning motion of smooth muscles.
• No absorption
• Propulsion occurs
o After the bolus is digested by the stomach, it is known as chime
o The chyme is moved from the stomach to the small intestine.
small intestine
• Most absorption of nutrients occurs here
o The small intestine is so long to allow for optimal absorption
o Also, on the inside of the small intestine, thee are little folds known as villus. Individual villus have microvilli, or more folds within the fold. This allows for more absorption of nutrients into the tissue. There are capillaries at the end of the villi to allow nutrient absorption into the blood.
• Most digestion occurs in the small intestine
o Chemical digestion
• Using enzymes
• The pancreas and small intestine both produce lots of kinds of enzymes that are able to digest everything:
• Carbohydrases-digest carbohydrates
• Proteases-digest proteins
• Lipases-digest lipids
• The esophagus and the small intestine do not have the thick mucus of the stomach to protect from acids.
o As chyme is released into the small intestine, the pancreas releases a base known as bicarbonate, which helps to neutralize the acid.
o Chyme is moved into the small intestine little by little. This protects from acidity and allows the most efficient digestion.
o In the esophagus, sphincter valves protect from acids
• Sometimes, they don’t close tightly enough, creating heart burn
• Propulsion
o Moves chyme and bile into the large intestine
accessory organs
Accessory Organs:
Organs that serve multiple functions, not just digestion.
• Liver
o A very large organ.
o Makes bile, which contains a group of chemicals that are emulsifiers. Emulsifiers help to mix fats and watery solutions in the small intestine, allowing enzymes to break them down.
o Made in the liver, stored in the gallbladder, secreted into the small intestine.
• Pancreas
-makes enzymes
-hormones (insulin, glucagon)
• Gallbladder
o Secretes bile into the small intestine
stimulus: rising blood glucose
e.g. after eating a carbohydrate-rich meal
• The pancreas is stimulated to release insulin into the blood
o The body cells then take up more glucose
o The liver takes up glucose and stores it as glycogen
• Blood glucose level declines to a set point; stimulus for insulin release diminishes
stimulus: low blood sugar
e.g after skipping a meal
• The pancreas is stimulated to release glucagon into the blood
o This causes the liver to break down glycogen and release glucose into the blood
• Blood glucose rises to a set point; stimulus for glucagon release diminishes.
Negative feedback regulation: body temperature
- Blood temperature decreases
- A signal is sent (via blood) to the brain, control center
- The brain sends the message that it is “too cold” to the skin (via nerves)
- Heat is conserved by constricting blood vessels and not sweating
- Blood temperature increases
- A signal is sent to the brain, control center (via blood)
- Via nerves, the brain sends the signal “too hot”
- Heat is released from the body by blood vessels dilating and sweating
Diabetes:
There is no cure for diabetes. It is a lifelong disease.
• Symptoms: dehydration, thirst, frequent urination, elevated blood glucose
• 24 million in people in the US have diabetes.
type one diabetes
Type one: • Considered to be an autoimmune disease. • Insulin dependent o The pancreas does not produce insulin • Juvenile onset
type two diabetes
• Noninsulin dependent
o These people are able to make insulin
• Adult onset?
o Now, a lot of young people are getting this in the United States
sponge digestion
Found in the ocean, sometimes fresh water. There cells are not organized into layers, and they do not have tissues. Thus, they don’t have organs or organ systems, and because of this, they digest things inside their cells (intracellular digestion).
- They get their food from the water, and through phagocytosis, take it into their cells.
- All over the sponge there are tiny openings known as Ostia. They usually have one larger opening known as the Asculum. The water flows in through the Ostia and out through the Asculum.
- They feed on really small food, like algae and bacteria. With the tails on the flagellates, they trap the particles from the water. Therefore, sponges are filter or suspension feeders.
Blind gut (flat worms)
Aquatic, living mostly in fresh water, flat worms have radial symmetry.
• Flat worms have tissues, allowing them to form organs (tissue is necessary for organs). They have three germ tissue layers, allowing them to have some organs. However, because flat worms don’t have a body cavity, there is not space for a lot of organs.
tissues:
o Ectoderm
o Mesoderm (lots of this in flatworms)
o Endosperm
- Flat worms don’t have a respiratory system, they are thin because it allows gases to diffuse across their skin.
- Their digestive system has a mouth. Their pharynx gets pushed our of the body so it can take up food. Then it goes into an intestine/digestive tract. Whatever is not digested goes our of the same opening because there is only one opening.
why is human digestion more efficient than flat worm digestion?
o Human digestion is more efficient because there are more specialized organs. We have more efficient digestion and better absorption. Without a one way gut, too many things are happening in one place, they are not able to extract as many nutrients from their food.
One-Way Gut (earthworms)
Earthworms are annelids. They have visible segmentation. Other members of this phylum include leeches and marine worms. All segmented worms require moisture. This allows them to diffuse oxygen across their skin, as they don’t have respiratory systems.
• Extracellular digestion
• They have a one-way gut like humans and most other animals
what is the function of the respiratory system?
You take in oxygen and exhale carbon dioxide. When you inhale oxygen, it is taken to your blood so it can go to your cells for cellular respiration. The carbon dioxide you exhale is the waste from cellular respiration.
the process of breathing
• When you inhale, air enters the body through the nasal cavity. In your nose, there are hairs and mucus to prevent things other than air from entering the respiratory passage. It also warms and moistens the air, which prevents change in body temperature, and because air is warmed, it is more affective for diffusion.
• When the air enters the body, it goes to the pharynx, the shared space with the digestive system.
• Then it goes to the larynx, which is commonly known as the voice box or vocal cords. Over the larynx, there is a shield of cartilage to prevent from external damage.
• Then, the air goes to the trachea, which also has protective rings of cartilage
o Inside the trachea, there are mucus and cilia. If you swallow something that irritates the respiratory tract, the cilia beat upwards towards the mouth. The invader is coated with mucus, and as it goes up, it becomes an irritant and you cough it up to your mouth to spit it out.
• The trachea then branches to the right and left bronchus.
• The bronchus branches then into small tubes called bronchioles, which are inside the lungs.
o Cartilage surrounds this to prevent from compression and allow air to continuously enter the lungs.
• The lungs are made up of alveoli
o They are one cell thick and moist to allow for good diffusion.
o There are more than 350 alveoli in a lung
your diaphragm
inhalation:
When you take in oxygen, your diaphragm contracts and moves down, causing high volume of air in the lungs and low pressure, which leads to gas flowing into the lungs.
exhalation:
Your diaphragm relaxes and pushes up and the ribcage pushes back down. Increase in pressure but low volume. The gas moves from the lungs from an area of high pressure in the lungs to an area of low pressure outside the lungs.
