Gen Bio, stuff from exam 3

Muscle hierarchy

Muscle → made of long cylindrical cells (muscle fibers), full of filaments (myofibrils), made of repeating units called sarcomeres, made of thick and thin filaments, Thin made of actin, thick made of mysoin

Cardiac cells

Striated, all fire togther, can generate implulse on their own, they are branched cells.

Smooth muscle

Wall of digestive tract, bladder, uterus blood vessels, Not attached to bone, not striated, no T tubules, no well-developed SR

Less efficient, slower contractions and relaxation

3 types of skeleton

Hydrostatic skeleton: fluid-filled cavity, Closed, fluid under pressure: Cnidarians, nematodes, annelids

Exoskeleton External, non-living – does not grow: Arthropods,chitin, protection and movement, Mollusks – CaCO3 – just protection

Endo skeleton: echinoderms and chordantes , can be cartilage (flexible skeletal tissue,chondrocytes,) or bone (Rigid skeletal tissue, dynamic clacium carbonate, calcium phosphate)

4 stages of food processing

Ingestion - food into cavity

digestion - macromolecules to monomers

absorption - cells take up monomers

elimination - undigested, pass out of system

Components of human digestion

Alimentary canal - complete digestive tract

Acessory glands - secrete digestive juices (pancreas, gallbladder, liver salivary glands)

Peristalsis - contractive waves in smooth muscles, moves food

Sphincters, circular muscular valves, keeping things contained in proper compartments

Food processing Pre ingestion

Triggered by NS, stimulates salivary glands

Food processing prior to stomach

Mechanical - teeth

Chemical - amylase

Mucus - proctective barrier, lubricant, helps create bolus

Tounge - moves food, creates bolus

Swallowing and anatomy involved

Food in mouth moves to pharynx(contains openings of trachea and espohagus), epiglotis covers trachea so food moves through esphogeal sphincter into esphogus

Esphogus - muscular tube connecting pharynx to stomach, bolus moves to stomach via peristalsis

Cardiac Sphincter - opens when bolus moves to stomach from esphogus, closes when food has entered

Food processing in stomach

Elastic can hold ~2 liters, stomach lining replaced every 3 days

has pits with gastric glands.

specific cells in stomach

Mucus cells - secrete mucus - protection + lubricant

Chief cells - secrete pepsinogen

peritial cells - H+ cells pushed against gradient into stomach, Cl- cells taken from blood, put into the stomach creating HCl

function of Hcl in stomach

PH of stomach, antimicrobrial

HCl, changes pepsinogen’s shape, taking of its “safety cap” turning it into pepsin. Once pepsin is produced, pepsin molecules can make pepsinogen into pepsin by themselves without hcl and begin turning proteins into peptides.

Pepsin is an endopiptidase, if a protein were a pearl necklace, endopiptidase cuts the necklace anywhere, allowing for large proteins to be cut into smaller ones very quickly

Stomach processing results in _____, wich enters _____

Chyme - partially digested carbs, small polypeptides, undigested material

enters small intenstine via pyloric sphincter

Food processing in small intestine

Duodenum: first part, where most chemical digestion occurs

Jejunum: middle part between duodenum and ileum

Ilium: lower portion

Carb digestion

Polysaccharides, disaccharides to monosaccharides

Oral cavity – salivary amylase

SI – pancreatic amylase, disaccharidases

Protein digestion

Polypeptides to amino acids

Stomach – pepsin

SI – pancreatic trypsin, chymotrypsin, dipeptidases, carboxypeptidases, aminopeptidases

Nucleic Acids

DNA, RNA to nitrogenous bases, sugars, phosphates

SI – pancreatic nucleases, nucleotidases, nucleosidases, phosphatases

Lipids

bile salts from the liver emulsify large fat masses into tiny droplets to increase surface area. Second, pancreatic lipases chemically hydrolyze these droplets into absorbable glycerol, fatty acids, and monoglycerides.

Absorption in small intestine

absorption via villi and microvilli in small intestine, most villi contain capillaries

What enters the large intestine

Some undigested protein, fats, carbs remain

Indigestible material – cellulose, dead cells

Function of LI

Entry regulated by ileocecal valve,

mostly water recovery, explusion of waste via anus, not involved in metabolism

Functions of Liver

SI absorbs nutrients wich enters blood through capillaries wich all meet at the hepatic portal vein.

hepatic portal vein → nutrient rich blood to liver who Detoxifies, produces proteins and and removes excess glucose then sends blood to heart to circulate throughout body.

Respiration, broad conceptual.

Gas exchange with enviornment

small aquatic organisms do not require specalized respiratory structures because their SA:V ratio is fine.

Larger aquatic and terrestrial organisms require moist specialized structures to facilitate gas exchange

Necessary characteristics of specialized respiratory structures

Thin walls, must reach blood in time

Large surface area - SA:V ratio

Moist - allow for diffusion, o2 must be dissolved to pass through membrane

Many blood vessels - whisk away oxygenated blood, maintain gradient

CC respiratory structures

Body surfaces - simple, small, must be moist even if terrestrial and insefficent

Gills - gas exchange in water, countercurrent exchange, maximises o2 diffusion

Tracheal System - system of air filled tubes (ducts), no circulatory system required

Lungs: Specialized structures for respiration in terrestrial vertebrates

regulation of breathing

Higher metabolic rate = more co2 in blood = lower ph of blood, triggers body to blow off co2 (panting)


increased metabolic activity → increase CO2. some CO2 dissolves in blood to beomce bicarb ions, some becomes to hemoglobin and some binds to plasma in its original gaseous form, this is the co2 that passes through the BBB and enters CSF where, as a result of fewer buffer proteins and a presence of water, it dissolves, releasing h+ ions. These H+ ions are detected immediately by chemoreceptors in the medulla (CSF coats medulla) and medulla triggers respiration to increase to blow off co2 and reduce aciditiy.

osmoregulation

osmoconfomer - Body fluids at equilibrium with surrounding seawater – isosmotic

osmoregulator - Control internal osmolarity independent of external environment

Can live in inhospitable or variable environments

Terrestrial vertebrates - must be osmoregulators.

Nitrogenous waste

Proteins + nucleic acids broken down for energy → nitrogenous waste

Deamination, removal of amino group generates ammonic (toxic)

Types of nitrogenous waste

Ammonia – highly soluble, low E required, but toxic

Urea – low toxicity, but higher E requirement and requires water to excrete

Uric acid – very high E requirement but insoluble and low toxicity