WEEK 9

6 essential nutrients

body needs but can’t make: water, 12 proteins, carbohydrate, 3 fat, 16 vitamin, 60 minerals

suspension feeders

filter food from water (whales)

fluid feeders

suck up nutrients (insects and some amphibians)

bulk feeders

consume large pieces of food (humans and many animals)

substrate feeders

live on and eat food source

deposite feeders

sift to feed (worms)

gastrovascular cavity

digestion and distribution of nutrients for extracellular digestion

digestive tube (alimentary canal)

two openings (mouth and anus)

salivary glands

mouth, pancreas, liver, and gallbladder

digestive systerm

ingestion (taking in), digestion (breaking down), absorption (into cells), assimilation (make food part of cell), elimination (removing unused food)

chyme

Semi-fluid mass of partially digested food.

HCL+pepsin+ contractions (peristalsis)

duodenum

First section of the small intestine where most chemical digestion occurs.

pancrease produces sodium bicarbonate which neutralizes acid

jejunum

second part of small intestine: absorbs sugars, amino acids, and fatty acids

lleum

last part of small intestine: remaining nutrients and vitamins

bile

made in liver, stored in gallblader: digests fats and fat soluble vitamins

small intestine

increases rate of nutrient absorption- diffusion and active transport throughout its length.

large intestine

water absorption, cecum helps with feces formation and fermentation

elimination

colon completes recovery of water (feces become more solid as it flows through) feces are stored in rectum

evolutionary adaptations

carnivores have large, expandable stomachs. herbivores/omnivores have longer alimentary canals since veggies take longer to digest

fermentation chamber

special section where mutualistic microorganisms digest cellulose

production of gastric juice

1: pepsinogen and HCL go into lumen of stomach

2: HCL turns pepsinogen into Pepsin

3: pepsin activates other pepsinogen and breaks down proteins

Fat digestions in small intestine

1: bile breaks down fat into triglycerides

2: lipase breaks triglycerides into fatty acids and monoglycerides

3: products diffuse into epithelial cells and reformed into triglycerides

4: triglycerides are packaged into chylomicrons and released into the lymphatic system.

interstitial fluid

links exchange surfaces to body cells

open circulatory system

hemolymph (blood+interstitial) bathes the organs directly (insects and arthropods)

closed circulatory system

blood is contained within vessels, allowing for more efficient transport of nutrients and oxygen. (vertebrates)

features of circulatory system

1: circulatory fluid

2: interconnecting vessels

3: muscle pump

Gills

outfoldings of the body that create a large surface area for gas exchange

Fish gills

• use countercurrent exchange, where blood flows into the opposite direction to water passing over the gills

• blood is always less saturated with O2 than the water it meets

Tracheal Systems in Insects

separate circulatory and respiratory

Lungs

• infolding of the body surface

• size if related to metabolic rate

Mammalian Respiratory systems

• air goes into lungs and passes to alveoli for gas exchange

pharynx

directs air to the lungs and food to the stomach

pulmonary edema

fluid in interstitial space increases diffusion distance. Arterial PCo2 increases, leading to hypoxia.

Emphysema

destruction of alveoli means less surface area for gas exchange

Fibrotic Lung Disease

thickened alveolar membrane slows gas exchange, and ventilation

Bird breathing

have air sacks to keep air flowing through the lungs

positive pressure breathing

forces air down the trachea by gulping- frogs

negative pressure breathing

the diaphragm contracts, creating a vacuum that draws air into the lungs.

pigments for gas exchange

increase the amount of oxygen carried in blood (hemoglobin)

hemoglobin curve

in low O2 conditions, is decreases affinity, in fetuses it has a higher affinity of oxygen

adaptations of diving mammals

• myoglobin proteins store oxygen (higher affinity)

• glide instead of swim

• route blood to vital tissues

• get ATP through fermentation

osmoconformers

are iso-osmotic with their surroundings and do not regulate their osmolarity (salt water fish)

osmoregulators

use energy to control water uptake and loss (fresh water fish)

seagull secretion

epithelial cells move solutes on the gills or nasal glands to excrete excess salt.

key functions of excretory systems

filtration, reabsorption, secretion, and excretion.

nephron

• glomerulus: ultrafiltration

• Proximal convoluted tube: reabsorbes nutrients

• descending loop: water goes out (passive)

• ascending loop: NaCl goes out (active)

• distal convoluted tube: reabsorbs water and ions, regulates pH

• collecting duct: reabsorbs water and solutes depending on ADH