BIOLOGY 211-TEST1

BIOLOGY 211-TEST1

DIGESTIVE SYSTEM

CatabolismMetabolismAnabolism

HYDROLYSIS DIGESTION CATABOLISM Addition of H2O

FOUR (4) LAYERS OF ALIMENTARY TRACT

1. MUCOSA Inner most layer Primarily Epithelium & Mucus Cells

2. SUBMUCOSA 2nd Layer Contains Blood vessels, Nerves, Lacteals(= Lymph Vessel)

3. MUSCLE Two (2) Layers

1. Circular Fibers Inner most

2. Longitudinal Fibers

4.SEROSA Visceral Peritoneum covers organs Parietal Peritoneum lines peritoneal cavity

MOUTH Lined with Stratified Squamous

MASTICATION Process of Chewing

TONGUE Lingual Frenulum (Anchors Tongue)

PAPILLAE Vallate, Fungiform, Filiform

UVULA

SOFT PALATE rises to close nasopharynx while swallowing

TONSILS Palatine (Swell with infection)

Pharyngeal (=Adenoids)-

Lingual

SALIVARY GLANDS Secrete Saliva (Contains HCO3). PH 6.5-7.5

GLANDLOCATIONSECRETIONDUCT

ParotidIn front and below earClear, watery, amylaseStensens

SubmandibularInside surface of mandibleSerous, some mucousWhartons

SublingualUnder tongueThick mucus

PHARYNX - Nasopharynx

Oropharynx Laryngopharynx

Bolus ball of masticated food that passes from the mouth to the stomach

DEGLUTITION Swallowing

PERISTALSIS Contractions of Alimentary Tract that moves food

ESOPHAGUS 25 cm long Links mouth-pharynx to stomach

Lined with Stratified Squamous & Mucous cells

RUGAE Folds in lining of stomach

STOMACH Contains Three (3) layers of Muscle

1.Oblique -

2. Circular

3. Longitudinal

Lined with Columnar Epithelium Gastric Glands secrete Gastric Juice

SECRETIONS OF GASTRIC GLANDS:FUNCTIONS:

Pepsinogen Secreted by Chief CellsForms Pepsin

Pepsin Formed when HCl acts on PepsinogenDigests Proteins

HCl by parietal cellsActs on Pepsinogen

Mucus By Goblet cells & Mucus glandsAlkaline Protects Lining

Intrinsic Factor By Parietal CellsAids in Vitamin B12 Absorption

GASTRIN Increases Gastric Activity Secreted by Stomach

PARASYMPATHETIC NERVOUS SYSTEM Increases Gastric Activity

SYMPATHETIC NERVOUS SYSTEM Decreases Gastric Activity

ENTEROGASTRIC REFLEX

Starts in Intestine and goes to Stomach Slows down Peristalsis when impulses travel from Intestine to CNS, then to Stomach via Vagus Nerve

CHOLECYSTOKININ Secreted in Intestine in response to Chyme (passed from Stomach to Small Intestines) with a high fat content causes Stomach to slow down PeristalticActivity

GASTRIC ABSORPTION H2O, Glucose, Salts, Alcohol, Drugs

PYLORUS Valve between Stomach and Duodenum

SMALL INTESTINE -18 ft. - 20 ft. In CadaversThree (3) Sections:

Duodenum 2 x 12

Jejunum Thicker wall; Greater diameter than lleum

lleum

MESENTERY Network of Blood Vessels, Nerves, Lymphatic Vessels

GREATER OMENTUM

LIVER:

Largest Organ in the Body

RIGHT & LEFT LOBES, QUADRATE & CAUDATE LOBES

FALCIFORM LIGAMENT Separates Right & Left Lobes

CORONARY LIGAMENT Fold of Visceral Peritoneum that attaches Liver to Diaphragm HEPATIC LOBULES Functional unit of Liver

Consist of Hepatic Cells that radiate outward from a Central Vein

HEPATIC SINUSOIDS Cavities lined with Kupffer Cells that carry out Phagocytosis

HEPATIC CELLS Produce Bile which Emulsifies Fat.

PANCREAS Acinar Cells secrete Pancreatic Juice

Components of Pancreatic Juice:

ZYMOGEN GRANULES Store inactive Protein splitting Enzymes in the Pancreas1.TRYPSINOGEN (Inactive) acted upon Enterokinase (an enzyme) in Small Intestine (Duodenum) to become

2. TRYPSIN which breaks down proteins

3. CHYMOTRYPSIN > Activated in presence of Trypsin & they also work on proteins

4. CARBOXYPEPTIDASE > Activated in presence of Trypsin & they also work onproteins

5. RIBONUCLEASE > Nucleases break down RNA into Nucleotides

6. DEOXYRIBONUCLEASE > Nucleases break down DNA into Nucleotides

7. BICARBONATE IONS Respond to Secretin (Hormone) Secreted in SmallIntestine in response to Acid Chyme

8. SUCRASE Breaks down Carbohydrates

9.LIPASE Breaks down TriglyceridesFatty Acids & Monoglyceride

SMALL INTESTINE Lined with Columnar Epithelium & Goblet Cells

PLICAE CIRCULARES Circular Fold of the Intestine Lining

VILLI Folds of Intestine Lining- (Fingerlike)

INTESTINAL GLANDS {In Mucous Lining between Adjacent Villi} Secrete Watery Fluid to aid in Absorption

MICORVILLI Fine Extensions of Individual Columnar Cells (At Free Surface) increases surface area

BRUNNERS GLANDS {In Proximal Part of Duodenum}Secrete Viscid, Alkaline Mucus

SECRETED FROM MICROVILLI OF SMALL INTESTINE

SUCRASEBreaks Down Sucrose

PEPTIDASEBreaks Down Protein

LACTASEBreaks Down Lactose

LIPASEBreaks Down Fat (Triglycerides)

ABSORPTION IN SMALL INTESTINE

CARBOHYDRATE By Active Transport or Facilitated Diffusion

PROTEINS Active Transport

LIPIDS Simple Diffusion

MICELLES CHYLOMICRONS

LARGE INTESTINE MAIN FUNCTIONAbsorption of H2O & Electrolytes

COLON: ASCENDING, TRANSVERSE, DESCENDING, SIGMOID

CECUM

APPENDIX, VERMIFORM

ILEOCECAL VALVE Between lleum & Cecum

TENIA COLI Three (3) Muscle Bands in Wall of Colon

HAUSTRA Pouches Formed as a Result of Tenia Coli

EPIPLOIC APPENDAGE Fat

MUCOUS CELLS Very Abundant in Colon

BACTERIA - Break down Cellulose for Energy (A Carbohydrate & SynthesizeVitamins K, B12, Thiamine, Riboflavin

COLOSTOMY

DIARRHEA (Peristaltic Rush)

CIRRHOSIS

HEPATITIS A, B, C, D

Entamoeba gingivalis (Commensal of gums)

Giardia intestinalis (Parasite of Small Intestine) Causes Giardiasis

Entamoeba histolytica (Intestinal Parasite) Causes Amoebic Dysentery

Diphyllobothrium latum - (Broad-fish Tapeworm-up to 6o ft. long) Intestinal Parasite absorbs Vitamin B12 from its host

Taenia saginata Beef tapeworm

Taenia solium Pork tapeworm

Ascaris lumbricoides Roundworm

BIOLOGY 211- TEST 1

DIGESTIVE SYSTEM

Introduction The digestive system receives food, modifies molecules, carries on absorption, and eliminates unused residues.

It consists of an alimentary canal and several accessory organs.

General Characteristics of the Alimentary Canal Various regions of the canal are specialized to perform specific functions.

1.Structure of the wall a.The wall consists of four layers.b.These layers include mucous membrane, submucosa, muscular layer, and serous layer.2. Movements of the tube.a.Motor functions include mixing and propelling movements.b.Peristalsis is responsible for propelling movements. 3.Innervation of the tube is by the autonomic nervous system. a.Parasympathetic impulses generally cause an increase in digestive activities; sympathetic impulses generally inhibit digestive activities.b. Sympathetic impulses are responsible for the contraction of certain sphinctermuscles that control movement through the alimentary canal.

The Mouth The mouth is adapted to receive food and begin preparing it for digestion. It also serves an organ of speech and pleasure. 1.The cheeks and lipsa.Cheeks form the lateral walls of the mouth.b.Lips are highly mobile and possess a variety of sensory receptors useful in judging the characteristics of food.2. The Tonguea.The tongue is a thick, muscular organ that aids in mixing food with saliva and moving it toward the pharynx.b. its rough surface (contains papillae) aids in handling food and contains taste buds.c. Lingual tonsils are located on the root of the tongue.3. The palatea.The palate comprises the roof of the mouth and includes hard and soft portions.b.the soft palate closes the opening to the nasal cavity during swallowing.c.Palatine tonsils are located on either side of the tongue in the back of the mouth.d.Tonsils consist of lymphatic tissues, but are common sites of infections and maybecome enlarged so that they interfere with swallowing and breathing.

DIGESTIVE SYSTEM continued

4. The Teetha.Two sets develop in sockets of the mandibular and maxillary bones.b.There are twenty deciduous and thirty-two permanent teeth.c.They function to break food into smaller pieces, increasing the surface area offood that is exposed to digestive actions.d. Different kinds are adapted to handle foods in different ways, such as biting,grasping, or grinding.e. Each tooth consists of a crown and root and is composed of enamel, dentine, pulp,nerves, and blood vessels.f. Dental carries involve decalcification of enamel and erosion of the teeth.

The Salivary Glands Salivary glands secrete saliva, which moistens food, helps bind food particles together, begins digestion of carbohydrates, makes taste possible, helps cleanse the mouth, and regulates pH in the mouth. 1.Salivary secretionsa.Salivary gland includes serous cells that secrete digestive enzymes and mucouscells that secrete mucus.b. Parasympathetic impulses stimulate the secretion of serous fluid.2. The parotid glandsa.These are the largest of the salivary glands.b.They secrete saliva rich in amylase that begins the digestion of carbohydrates. 3.The submaxillary glandsa.These are located in the floor of the mouthb.They produce saliva that is more viscous than that of the parotid glands. 4.The Sublingual glandsa.These are located in the floor of the mouth.b.They primarily secrete mucus.

The Pharynx and Esophagus The pharynx and esophagus serve only as passageways. 1.Structure of the pharynxa.The pharynx is divided into a nasopharynx, oropharynx, and laryngopharynx. 2.Its muscular walls contain fibers arranged in circular and longitudinal groups. 3.The swallowing mechanism (deglutition)a.The act of swallowing occurs in three stages.(1)Food is mixed with saliva and forced into the pharynx.(2)Involuntary reflexes move the food into the esophagus.(3)Food is transported to the stomach.

DIGESTIVE SYSTEM continued

The Stomach The stomach receives food, mixes it with gastric juices, carries on a limited amount of absorption, and moves food into the small intestine.

1.Parts of the stomacha.The stomach is divided into cardiac, fundic, body and pyloric regions.b.The pyloric sphincter serves as a valve between the stomach and the smallintestine. 2.Gastric secretionsa.Gastric glands secrete gastric juice.b.Gastric juice contains pepsin, hydrochloric acid, and intrinsic factor. 3.Regulation of gastric secretionsa.Gastric secretions are enhanced by parasympathetic impulses the hormone,gastrin.b. Three stages of gastric secretion include cephalic, gastric, and intestinal phases.c. Presence of food in the small intestine reflexly inhibits gastric secretions. 4.Disorders of gastric secretionsa.A breakdown of protective mechanisms or excessive secretions may lead toulcers in the stomach or duodenum.b. The cause of ulcers seems to involve emotional stress.c. Treatment for ulcers eliminates aggravating factors and gives damaged tissuestime to heal. In extreme cases, fibers of the Vagus nerve are cut to reducegastric secretions.5. Gastric absorptiona.The stomach is not well adapted for absorption.b.A few substances such as water and other small molecules may be absorbedthrough its wall.6. Filling and emptying actionsa.As the stomach fills, its wall stretches, but its internal pressure remainsunchanged.b. Mixing movements aid in producing chyme; peristaltic waves move the chymeinto the small intestine.c. The rate of emptying depends on the fluidity of the chyme and the type of foodpresent.d. The upper part of the small intestine fills, and an enterogastric reflex causes thePeristaltic waves in the stomach to be inhibited.e. Vomiting results from a complex reflex that can be stimulated by a variety offactors.

The Pancreas 1.Structure of the pancreasa.The pancreas is closely associated with the duodenum.b.It produces pancreatic juice that is secreted into a pancreatic duct.c.The pancreatic duct leads to the duodenum. 2.Pancreatic juicea.Pancreatic juice contains enzymes that can split carbohydrates, proteins, fats,and nucleic acidsb. It has a high bicarbonate ion concentration that helps to neutralize chyme and causes the intestinal contents to be alkaline.3. Regulation of pancreatic secretiona.Secretin from the duodenum stimulates the release of pancreatic juice thatcontains few digestive enzymes but has a high bicarbonate ion concentration.b. Cholecystokinin from the intestinal wall stimulates the release of pancreatic juicethat has a high concentration digestive enzymes.

The Liver 1.Functions of the livera.It is the largest gland in the body.b.Liver carries on a variety of vital functions.c.Bile is the only secretion that directly affects digestion 2.Structure of the livera.The liver is a highly vascular organ, enclosed in a fibrous capsule, and dividedinto lobes.b. Each lobe contains hepatic lobules, the functional units of the liver.c. Bile from the lobules is carried by bile canals to hepatic ducts that unite to formthe common bile duct.3.Composition of bilea.Bile contains bile salts, bile pigments, cholesterol, and various electrolytes.b.Only the bile salts have digestive functions.c.Bile pigments are products of red blood cell breakdown. 4.The gallbladder and its functionsa.The gallbladder stores bile between meals.b.Release of bile from the common bile duct is controlled by a sphincter muscle. 5.Regulation of bile releasea.Release is stimulates by cholecystokinin from the small intestine.b.Sphincter muscle at the base of the common bile duct relaxes as a peristalticwave in the duodenal wall passes by.

6.Digestive functions of bile saltsa.Bile salts emulsify fats and aid in the absorption of fatty acids, cholesterol andcertain vitamins.b. Bile salts are reabsorbed in the small intestine.

The Small Intestine The small intestine extends from the pyloric sphincter to the large intestine. It receives secretions from the pancreas and liver, completes the digestion of nutrients, absorbs the products of digestion, and transports the residues to the large intestine. 1.Parts of the small intestinea.The small intestine consists of the duodenum, jejunum, and ileum.b.It is suspended from the posterior abdominal wall by mesentery. 2.Structure of the small intestinal walla.The wall is lined with villi that aid in mixing and absorption.b.Intestinal glands are located between the villi. 3.Secretions of the small intestinea.Secretions include mucus and digestive enzymes.b.Digestive enzymes can split molecules of sugars, proteins, fats and nucleic acids. 4.Regulation of small intestinal secretionsa.Secretions are enhanced by the presence of gastric juice and chyme and by the mechanical stimulation of distension.b. A hormone from the intestinal wall may also stimulate secretions. 5.Absorption in the small intestinea.Villi increase the surface area of the intestinal wall.b.Monosaccharides, amino acids, fatty acids and glycerol are absorbed by the villi.c.Villi also absorb water and electrolytes.d.Fat molecules with longer chains of carbon atoms enter the lacteals of the villi; other products of digestion enter the blood capillaries of the villi. 6.Movements of the small intestinea.Movements include mixing, peristalsis, and pendular movements.b.Overdistension or irritation may stimulate a peristaltic rush and result in diarrhea.c.The ileocealvalve control movement from the small intestine into the large intestine.

The Large Intestine The large intestine functions to reabsorb water and electrolytes and to form and store feces. 1.Parts of the large intestinea.The large intestine consists of the cecum, colon, rectum, and anal canal.b.The colon is divided into ascending transverse, descending, and sigmoidportions. 2.Structure of the large intestinal walla.Basically this wall is like the wall in other parts of the alimentary canal.b.Unique features include a layer of longitudinal muscle fibers that do notcover the wall uniformly, and fatty appendages in the serous layer.3.Functions of the large intestinea.The only significant secretion is mucus.b.The rate of mucus secretion is controlled by mechanical stimulation andparasympathetic impulses.c. Absorption is generally limited to water and electrolytes.d. Many bacteria inhabit the large intestine and may aid the body by synthesizingcertain vitamins.4. Movements of the large intestinea.Movements are similar to those in the small intestine.b.Mass movements occur two or three times each day.c.Defecation is stimulated by a defecation reflex. 5. The fecesa.Feces consist largely of water, undigested material, mucus, and bacteria.b.The color is due to bile salts that have been altered by bacterial actions. 6.Disorders of the large intestinea.Constipation occurs when feces become excessively dry and defecation becomesdifficult.b. Diarrhea is due to rapid movement of feces through the intestines; this interfereswith water absorption.

Nervous SystemsCentral Nervous System Brain and Spinal Cord

Peripheral Nervous System Cranial Nerves (12 pair) andSpinal Nerves (31 pair)

Autonomic Nervous SystemSympathetic Nervous SystemParasympathetic Nervous System

Neurons:Composed of cell body, dendrites, and axonCell Body:(= Perikaryon) contains cytoplasm and cytoplasmic organellesGanglion:a cluster of neuron cell bodiesNeurofibrils:support cell processesNissl bodies:similar to endoplasmic reticulumNerve fibers:dendrites and axonsDendrites:carry impulses toward from cell bodyAxon:carry impulses away from cell bodySchwann cells:special type of neuroglia that form a sheath around peripheral nervesMyelin:Lipid-protein that forms a sheath around the outside of an axonNeurilemma:the portion of Schwann cells that contain cytoplasm and nuclei and remainoutside the myelin sheathMyelinated fibers:white due to myelinUnmyelinated fibers:gray due to lack of myelin

NEUROGLIAL CELLS1.Astrocytes2.Oligodendrocytes3.Microglia4.EpendymaCELL MEMBRANE POTENTIALResting Potential When nerve cells are at rest and not conducting impulses.More sodium ions are outside and more potassium is inside. However, there are less negative ions and more positive ions outside. Thus, a positive charge results on the outside.

ACTION POTENTIAL (takes 1/1000 of a second); travels at a rate of 120 meters/sec onmyelinated fibers and at a rate of 0.5 meters/sec on unmyelinated fibers.

Polarized indicates there is an unequal distribution of ions on either side of a cellmembrane. The outside is usually positively charges with respect to the inside.

The polarization is affected by the ease with which ions can move through the membrane.Potassium is first with regard to ease, Sodium is second, and Calcium is third.

THE SYNAPSENEUROTRANSMITTERNEURONS BASED ON ANATOMICAL STRUCTURE1.Bipolar2.Unipolar3.Multipolar

NEURONS BASED ON FUNCTION

1.Sensory (= Afferent)-carries impulses towards the CNS2.Internuncial (Communicans) links sensory and motor neurons3.Motor (=Efferent) carries impulses away from CNS

Reflex Arcs

Simple Reflex ArcKnee Jerk ReflexWithdrawal Reflex

Types of Nerve and Nerve Fibers

Nerve

Somatic Afferent & Efferent FibersVisceral Afferent & Efferent Fibers

CHAPTER 11 NERVOUS SYSTEM

Meninges

Dura Mater thick, contains abundance of connective tissueDural sinusArachnoid Mater spider-web in appearanceSubarachnoid Space contains cerebrospinal fluidPia Mater contains blood vessels, lymph vessels, nerves

Spinal Cord

Cervical enlargement nerves to armsLumbar enlargement nerves to legsConus Medullaris cone shaped inferior end of spinal cordCentral Canal contains cerebrospinal fluidFilum terminale terminal filament of pia mater that anchors the spinal cord in thesacral-coccygeal region of vertebral columnFuniculi (contain longitudinal bundles of myelinated nerve fibers that comprise majornerve pathways called nerve tracts). A fasciculus is a bundle of myelinatedfibers and they are found within a funiculus.Gray Commissure

Ascending Tracts (= sensory)terminate in nucleus gracilis and nucleus cuneatus of the medulla oblongata

> Fasciculus GracilisFasciculus Cuneatus

Lateral Spinothalamic Anterior Spinothalamic

>terminate in thalamus Posterior Spinocerebellar Anterior Spinocerebellar>terminate in cerebellum

Descending Tracts (= motor)

Lateral Corticospinal Anterior Corticospinal Anterior Reticulospinal Medial Reticulospinal Rubrospinalterminate in spinal cord

Brain

CerebrumConvolutions (gyri) largest part of brain- for thinking, memoryCorpus Callosum bridge between cerebral hemispheresFissure (sulcus)Lobes Frontal, Parietal, Temporal, Occipital

Basal Ganglia Caudate nucleus, putamen, globus pallidus serve to relaymotor reflex from cerebral cortex to spinal cord

Ventricles -Lateral - #1 in left hemisphere, #2 in right hemisphereThirdFourthInterventricular foramen link lateral ventricles to 3rd ventricleCerebral Aqueduct (aqueduct of Sylvius) links 3rd with 4th ventricle

Ependyma cells line ventricles

Cerebrospinal fluidChoroid Plexuses produce cerebrospinal fluid

Diencephalon surrounds the third ventricleOptic Chiasma convergence of Optic Nerves (I)Infundibulum stalk of Pituitary GlandPituitary Gland (hypophysis)Pineal Gland an Endocrine glandThalamus receives all sensory impulses coming into the brain except smellHypothalamus HomeostasisLimbic System Emotions

Brain Stem composed of the following

Mesencephalon = Midbrain 3" in length4

Cerebral Aqueduct runs through the center of midbrainCorpora Quadrigemina composed of 2 superior colliculi (slight reflexes) and 2 inferior colliculi (hearing reflexes)Red Nucleus

Pons

Medulla Oblongata controls respiratory rate, cardiac rate, vasomotor of blood vessels

Cerebellum involved in equilibrium and muscular coordinationDenate nucleusArbor Vitae tree-like in appearance

Peripheral Nervous System

Cranial Nerves (12 pr)

No.NerveTypeFunction

IIIIIIIVVVIVIIVIIIIXXXIXII

Spinal Nerves (31 pr)

Cervical 8 prThoracic 12 prLumbar 5 prSacral 5 prCoccygeal 1 prCauda Equina (= horsetail)

Plexuses formed from anterior rami of specific spinal nervesCervical first four cervicalBrachial last four cervical and first thoracicLumbosacral lumbo-sacral complex

Sympathetic N.S. (-Thoracolumbar Div)

Preganglionic fibers originate from neurons in spinal cord. Neurons are located in all thoracic segments and upper 2-3 lumbar segments Their axons (Preganglionic fibers) exit the ventral root, go through the white ramus, synapse in the paravertebral ganglia (= sympathetic trunk) and the postganglionic fibers may also exit via a spinal nerve and synapse in the collateral ganglia of the abdomen.

(Short preganglionic fibers synapse long postganglionic fibers)

Parasympathetic N.S. (= Craniosacral Div)

Preganglionic fibers arise from neurons in the midbrain, pons, and medulla oblongata. They exit via cranial & sacral nerves, synapse in ganglia (terminal) near visceral organs, and post ganglionic fiber continues to specific organs or muscles.

The preganglionic fibers are white (myelinated) and postganglionic fibers are gray for both the sympathetic and parasympathetic systems.

Parasympathetic N.S.Sympathetic N.S.

Pre and post ganglionic fibers secretePreganglion fibers secrete acetylcholineacetylcholine and are called cholinergicand called cholinergic

Postganglionic fibers (= noradrenaline)secrete norepinephrine and are calledadrenergic

20