Lecture 03-04 Flashcards
Six classes of nutrients:
Carbohydrates Lipids Proteins Minerals Vitamins Water
Nutrients three jobs?
- Provide energy
- Form new body components
- Assist in various physiological functions/processes
Metabolism:
all chemical reactions that occur in the body
Anabolism:
combining smaller molecules into larger ones.
Catabolism:
breaking large molecules into smaller ones with release of energy.
Enzymes:
proteins that act as catalyss to sdpeed up chemical reactions.
Sugars, primary one used by body is
glucose
polysaccarides)
Stored in body as long chains called glycogen in liver and muscle cells.
Monosaccarides (short)
Monosaccarides (short) – from fruits and sugar cane.
Polysaccarides
from grains and vegetables
LIPIDS
many hydrogen bonds, so lots of stored energy
Triglycerides
storage
Phospholipids
cell membranes, myelin sheaths
Steroids
(e.g. cholesterol) – modified to become hormones and bile secretions (from liver). Excess stored in adipose tissue.
PROTEINS
Many functions: structural, transport, cell movement, enzymes, specialized functions such as hemoglobin)
Made up of amino acids (20 types)
During digestion, broken down to individual amino acids
Can be later rebuilt.
Liver can convert excess amino acids to triglycerides.
Large excess of amino acids lost in urine.
MINERALS
Inorganic nutrients required in small amounts
About 4% of total body weight (mostly in skeleton).
Macrominerals (needed at levels of over 100 milligrams a day): Calcium, Phosphorus, Sulfer, Sodium, Potassium, Chlorine, Magnesium
Microminerals (needed in only trace amounts): Iron,l Iodine, Copper, Zinc, Floourine, Manganese, Cobalt, Chromium, Selenium
VITAMINS
Do not provide energy or building materials, but act as co-enzymes (necessary for enzyme functions) Fat Soluble (absorbed with lipids in small intestine; can be stored in cells): A, D, E, K Water Soluble (absorbed with water in large intestine; excess excreted in urine, not stored): B, C, Pantothenic acid, Folic acid, Biotin
Fat Soluble
(absorbed with lipids in small intestine; can be stored in cells): A, D, E, K
Water Soluble
absorbed with water in large intestine; excess excreted in urine, not stored): B, C, Pantothenic acid, Folic acid, Biotin
METABOLISM
sum role of all cellular activities that maintain the body.
DIGESTION:
mechanical and chemical processes involved in breaking larger food particles down into smaller ones.
ABSORPTION:
process by which these (resulting) molecules pass from the gut tube to the bloodstream and lymphatic circulation.
MOUTH, Mechanical Digestion:
chewing (teeth), manipulation of food by muscles of mastication (V3), buccinator (VII), and tongue (XII)
MOUTH,Chemical Digestion:
salivary amaylase (initial carbohydrate breakdown) – starch breakdown
MOUTH, Absorption:
little or none (except for alcohol!)
DETAIL ON TEETH:
In maxilla or dentary:
Incisors (4): tearing and nipping.
Canines (2): slashing, tearing, shearing, biting.
Premolars (4): larger, complexly surfaced, for chewing and grinding.
Molars (6): even larger grinding teeth.
ESOPHAGUS:
Lined by striated muscle (not smooth). Important for passage of food, but…
No chemical or mechanical digestion.
First part of body in which PERISTALSIS takes place.
Empties into stomach at CARDIAC SPHINCTER.
PERISTALSIS
wave of muscular action that propels bolus of food down gut tube
STOMACH three main functions
- Storage
- Preparation of food before it moves to small intestine
- Testing area in case of “poisonous ingestion”.
- Not an absorptive structure
Stomach: Mechanical Digestion
Inner surfaace derived from endoderm. Three layers of smooth muscle (derived from mesoderm) to churn/mix food. Breaks food down and mixes with gastric secretions.
Rugae
folds on internal surface of stomach
- Increase surface area
- Allow distention.
- When not completely distended, allows food to be pushed up against ridges for further mechanical digestion.
Stomach-Movements – associated with parasympathetic autonomics
Vagus nerve (X)!
what are blood vessels
tubular structures, with particular named layers from innermost to outermost
layers of blood vessels innermost-outer
Tunica Intima, Tunica Media,Tunica Adventitia (or Tunica Externa)
lymphatic system
is circulatory system but does not have a pump and its a blind ended system- it starts at one end and dumps in another but doesnt go into a circut- it dumps into a cardiovascular system
does not carry blood that is red in color
It transports white blood cells to and from the lymph nodes into the bones
both the lympathic system and the circulatory system is dervived from?
mesoderm
pin in blood vessel where is it dervived from
mesoderm
blood carried with cardiovascular system usually grouped with what?
connective tissue
Blood derived from cells in bone marrow what does this mean?
ultimately) from mesoderm
what does the cardiovascular system include?
includes pump (heart) and associated vessels (arteries, veins, capillaries)
what are three main functions of blood?
transport, protection, regulation
describe transport importance in blood most imp
send oxygen to tissues, remove CO 2 from tissues that generate it, takes other kinds of cellular waste either chemicals or solids, moves important chemical stuff around ,nutrients, hormones, enzymes
describe protection importance in blood
immune response (white blood cells), blood clotting. help plug holes-clotting most of blood is water
describe regulation importance in blood
water balance, chemical levels, pH, body temperature.regulate a lot- deals with metabolism- because blood is mainly water it is a huge thermal buffer- water keeps us from over heating or being too cold
three main components of blood
RED BLOOD CELLS
WHITE BLOOD CELLS
PLASMA (about 55%)
what is plasma made up of.. percents?
About 90% of plasma is simple water, remaining 10%
gastrin
is a peptide hormone that stimulates secretion of gastric acid (HCl) by the parietal cells of the stomach and aids in gastric motility. tells vagus nerve parasympathtic food is coming
The Gastric Canal is the internal region of the stomach that is the most direct path between cardiac and pyloric sphincters –
where rugae are simple and longitudinal.This direct path allows passage of water even when rest of stomach is relatively full
Stomach: Gastric Secretions
Remember, inner lining derived from endoderm.
Primary gastric secretion: HYDROCHLORIC ACID (HCl) from Parietal Cells.
stomach secretion Mucous function?
– lubricates food, protects stomach lining from HCl.
stomach secretion function?Zymogenic Cells
(Chief Cells) – PEPSINOGEN. HCl cleaves pepsinogen into PEPSIN, which chemically digests proteins.
stomach secretion function?Entroendocrine Cells
secrete hormones that regulate stomach functions such as peristalsis, other secretions, etc.
stomach secretion function?Gastrin
astimulates secretion of HCl.
Gastrin secretion controlled by Vagus nerve. Can be stimulated by smell, taste, chewing, swallowing.
SMALL INTESTINE:
absorbs what?
completes what?
includes what?
Most of the absorption of nutrients and water.
Complete/finish chemical digestion of proteins, carbohydrates, and fats
Duodenum(first kink of the small intestine) , Jejunum, Ileum
explain the dudonenum and flow of food?
Glands dumping into duodenum via common bile duct
- Liver makes bile salts for digestions via bile duct.
- Products stored in gall bladder via cystic duct.
- Pancreas (usually directly into duodenum via pancreatic duct).
(FOREGUT) PANCREAS describe it? know where it is? endocrine and/or exocrine organ?
Both endocrine and exocrine organ. pancreatic duct in small intestine secretes hormones(endo) and digestive into a tube (exo)
Exocrine Secretion Vagal stimulation promotes secretion of three pancreatic enzymes?
1Pancreatic Lipase – splits large fats into smaller
2.Pancreatic amylase – breaks down polysaccarides into monosaccarides and disaccarides.
3Pancreatic Protyolytic Enzymes – inactive forms of the following secreted into duodenum:
Trypsin
Chymotrypsin
Carboxypeptidase
Enterokinase activates the trypsin. Trypsin activates the others
(FOREGUT) LIVER:
job?
1Bile Secretion – bile is extremely alkaline.
2Neutralizes acidic material passed from stomach to duodenum
3Aids in fat breakdown
Detoxification
Glycogen storage.
(FOREGUT) GALL BLADDER:
job?
1Although bile generated by the liver constantly it isn’t needed at all times – only when food passes.
2Gall bladder acts as storage awaiting food passage.
3Passes bile to common bile duct via cystic duct.
Morphology Review:
of the JEJUNUM AND ILEUM
sympathetics tell parasympathtics
1.Jejunum – about 2.5 meters ( 8 feet)
I2.leum – about 3.5 meters (11-12 feet)
3Great length increases absorptive surface area, and passage through it increases time for absorption.
Plicae Circulares define?.
– internal folds of small intestine.
Villi??
tall, pillar-like bumps arise from internal surface to increase surface area. Inside each one: arterial branch, venous branch, nerve, lacteal.
suffix ase means?
break down
Intestinal glands
clefts between villi (old name = “Crypts of Lieberkhun”).
MIDGUT: JEJUNUM AND ILEUM
Remaining Mechanical Digestion:
Peristaltic Contractions – propel mushed-up foodstuff
fats hard to break down then carbs and proteins
Segmenting Contractions in the jejunum and ileum
– circularly arranged bands of smooth muscle can constrict small intestine to point of occlusion. Functions to break up chyme, keeping it loose and mushy.
EMULSIFICATION in the jejunum and ileum
physical breakdown of lipid particles (usually to glycerol and free fatty acids) – primarily a function fo the bile.
PROTEIN DIGESTION in the jejunum and ileum
Trypsin and others finish breaking proteins to shorter polypeptides. AMINOPEPDIDASE breaks the down further into individual amino acids.
CARBOHYDRATE DIGESTION in the jejunum and ileum
“Disaccaridases” (many kinds) break complex sugars into smaller 2-ring sugars, and (mostly) glucose.
MIDGUT: JEJUNUM AND ILEUM
Absorption in the Small Intestine: 1.water 2carbs 3protein 4lipids
1WATER – 80-90% of water entering gut tube absorbed in small intestine.
2CARBOHYDRATES – primarily through microvilli of villi.
3PROTEINS – though columnar-shaped absorptive cells on the villi.
4LIPIDS – glycerol and free fatty acids combine with bile secretions to form a MICELLE (hydrophilic outer surface; lipids internally) allowing the to be absorbed across villi.
whats a micelle
hydrophilic outer surface; lipids internally) allowing the to be absorbed across villi.
decribe fat processing in JEJUNUM AND ILEUM
MICELLE absorbed across villi.
Once inside cells, housed in endoplasmic reticulum.
Lipids packed into protein coated droplets called CHYLOMICRONS.
Sent to lacteal of villus
MIDGUT: JEJUNUM AND ILEUM
VITAMIN AND MINERAL ABSORPTION:
1FAT SOPLUBLE VITAMINS
A – maintain epithelia
D – facilitate absorption and use of calcium
E – DNA, RNA, RBC formation,oxygen in RBC
K – needed for clotting
2WATER SOLUBLE VITAMINS absorbed with water.
3B-12 requires specialized protein carrier (in ileum).
LARGE INTESTINE: describe absorption? important vitamins? fine tuning of how much water you hang on too correlates to water in kidney regulation
Absorption: remainder of water to be absorbed (primarily in ascending and transverse regions) and careful water balance achieved here. Also some salts, certain vitamins.
what microorganims are involved in the large intestine?
Escheria coli (E. coli) – a bacterium – aid in final conversion of liquid waste into semisolid feces. Also synthesize vitamins K and B12
function of the descending colon?
: intestinal glands secrete mucous – facilitates movement of drier material, neutralizes acids of remaining bacteria.
FECES AND DEFECATION shit and shitting
Much of mass of feces is unusable material (cellulose or “roughage”) and dead bacteria.
DEFECATION (ELIMINATION)
process of expelling feces from terminal end of gut tube. Controlled by “defecation reflex”.
defincation process o shit
1Internal anal sphincter relaxes.
2Coelom pressurized (lateral and abdominal hypaxial muscles).
3Peristaltic waves pass through sigmoid colon.
4External anal sphincter relaxes (and feces exits body).
TION
out of body
important proteins in plasma
1Albumins – promote water retention ( thus maintaining normal blood volume & pressure)
2Fibrinogen – essential for blood clotting
3Globulins
-Alpha and Beta globulins function to transport fat-soluble materials and lipids.
-Gamma globulins are antibodies functioning in preventing certain diseases
blood
55% plasma
buffy coat 1%
45% erthryocytes
ERYTHROCYTES
describe the morphology
~ 2 microns thick
~ 7 microns across
Disc shaped
Concave on each side
Mature RBC have no nuclei.
Almost entire volume taken up by oxygen carrying molecule HEMOGLOBIN.
RED BLOOD CELL PRODUCTION
before birth? where?
After birth (normally): ? found where?
Before birth: yolk sac, liver, spleen.
After birth (normally): large cells of bone marrow of certain bones – vertebrae, sternum, hip, long bones.
After trauma: spleen can come back into service.
normal life span of RBC?
180 days 4 months
what is hemoglobin?
iron-rich molecule,Transport of oxygen accomplished
Hemoglobin is chracterized by
its ability to bind Oxygen where oxygen concentration is high, and release it where it is low. drop its where its low ay
“Heme” component is only 5% of actual molecule
but very important – the iron containing part
Reduced iron content in body reduces blood’s ability to carry oxygen
RBCs also
carry carbon dioxide,
Part carried in hemoglobin, but much is dissolved directly in the plasma
Most carbon dioxide converted to CARBONIC ACID by reaction with water.
know the equation?
CO2 + H2O -> H 2CO 3 -> H+ + HCO3-
RBC LIFECYCLE
generated by what?
Generated by HEMATOPOIETIC STEM CELLS in bone marrow.
innermost layer of a blood vessel is what- what are the sub catergories?
Tunica Intima (has three subcomponents):
Inner lining of simple epithelial cells attached to a basement membrane.
Middle layer of fine connective tissue made up of collagen.
Internal elastic lamina – outer elastic layer
why is there muscle in blood vessels?
regulate the size of the inside of blood vessel depending if your contracting a muscle restrict blood vessel
sympathtic response would cause blood vessels to open up to know what you do
tell blood vessels in parasymp like stomach to not have time for that to do it later
Tunica Media
smooth muscle, elastic fibers, other connective tissue components.
Tunica Adventitia (or Tunica Externa)–
mostly elastic and collagenous fibers. (In large vessels this layer has dedicated nerves, tiny blood vessels and lymphatics.)
The TUNICA MEDIA is relatively thin in?
thinner in veins
Veins usually have little or not smooth muscle
expect in the largest of veins.
which has valvues? arteries of bein
Veins have periodic valves to prevent backflow.
ARTERIES to ARTERIOLES
Smallest definable arteries are arterioles.
They have relatively more smooth muscular tissue, less elastic tissue.
Thus, they are more easily regulated by (autonomic) nervous control.
Very smallest arterioles (terminal arterioles):
Have no internal elastic layer.
Tunica media densely supplied with sympathetic nerve fibers.
VEINS TO VENULES
Some veins to have smooth muscle in them (the very largest).
Have same layers as arteries, but tunica media is much thinner.
Have relatively less elastic tissue.
Operate at low pressure.
Have periodic bicuspid-shaped valves to prevent backflow.
Smallest (venules) receive capillary blood – have no tunica media.
what are capillaries?
Blood to capillaries from arterioles.
Smallest and thinnest of vessels.
Usually constructed of only a single layer of tunica intima.
Greatest loss of blood pressure is at capillaries.
Gas transfer takes place across wall.
Nutrient transfer takes place across walls.
Blood from capillaries to venules.
The first blood vessels of the embryo form inside the ?? where do they form?
embryonic disc even before somites appear.
near the edge of the yolksac (a primitive condition inherited from macrolecithal organisms that stored yolk for food).
Angiogenetic cell clusters
clusters extend in an arc around the head end of the ventral opening of the yolk sac. Initially, this means that the angiogenetic cell clusters (and the blood vessel that forms from them) have the pattern of a “horseshoe” if viewed from a dorsal or ventral perspective.
explain heart development
An important point to understand is that the coelom runs up and down either side of the body.
At the head end, right underneath the developing pharynx, the coelom on the left communicates with the coelom on the right.
Thus, the coelom cuts across the midline here.
The brain grows at an incredible rate. It grows so fast that it makes the head bend around under the embryo’s body.
(For the same reason that the gut is subdivided into three parts), this is why the heart winds up on the VENTRAL SIDE of the body
early development heart describe
The part of the heart ventral to the gut tube is a single tube itself.
The tube exiting the heart at its cranial end is the ventral aorta.
However, the heart cannot remain a simple tube (like a fish), so it must be subdivided into a right and left side.
A septum subdivides the heart into a left and right side.
The tube exiting the heart at its cranial end is the ventral aorta. where else does it subdivide
It also subdivides:
The right side connects with the lungs.
The left side supplies the body.
(More later…)
