a&p ii-iii

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Unit III

Respiratory, Digestive, Urinary

Adaptations For Exchange:

1. Single Cell Layer Membrane

2. Selective Permeability (Differential)a. Simple Diffusion: across gradients

b. Osmosis

c. Facilitative Diffusiond. Active Transport

e. Cytosis

3. Extensive Surface Area

a. Membrane Undulations: A regular rising & falling or movement toalternating sides, movement in waves.

b. Viili

c. Microvilli

4. Communication with body cells via circulatory system5. Communication with outside environment

6. Process: Part of selective permeability adaptationa. Secretion: out

b. Excretion: out

c. Absorption: in

d. Reabsorption: reclaim

Exchange: The movement of substances across membranes

Digestive System Chapter 24:

Digestive Traits:

• Tubular & open @ both ends

• Extra cellular Hydrolysis

• Muscular

o Peristalsis

• Nervous & Hormone Control

Function:

• Chemical & Physical breakdown of preformed matter for use by the body

• Chemical:

o Macromolecules into smaller or simple productso CHO’s

o Lipids

o Proteins

o Needs enzymes (hydrolytic) & water

• Physical:

o Breakdown

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o Critical to increasing particle size & surface area (mastication)

o Larger surface are to be acted on by enzymes

• Use: Provides energy, growth, repair & maintenance

*Sensory information is critical to food selection:

• Vision• Olfaction

• Tactile

• Gustation

*Follow Macromolecules Down The Digestive Tract:

A: Salivary Gland:

• Exocrine ducts into oral cavity

• Parotid Gland: Largest salivary gland that produces mostly watery saliva

• Submandibular Gland: Mixed glands with more serous than mucous

alveoli• Sublingual Gland: Smallest gland, mixed gland contains some serous

alveoli but mostly mucous alveoli

B: Oral Cavity:

• Physical breakdown of food through mastication

o Teeth: Critical to mastication, can cut & grind food

o Tongue: Forces food into oropharynx

o Saliva: Lubrication

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• Omnivore: Permits diverse diet, canines, incisors, molars

• Chemical breakdown is initiated

o Salivary Amylase: starch splitting enzyme, that helps increase

surface area

o Partial Hydrolysis of polysaccharides form amylase

• Broken down into smaller particle once it reaches the pharynx• PH 6.5-7.2

C: Pharynx:

• Nasopharynx: Back of soft palate, break down does not occur here

• Oropharynx: tongue forces food into oropharynx

o Peristalsis & Swallowing initiated here

D: Esophagus:

• Muscular tube

• Mucousal lining

• Passageway

E: Stomach:• PH between 1&2

• Muscular

• Diverse epithelium

o Parietal Cells:

Secratory in nature

Associated with HCL

Intrinsic Factor: Effects absorption of B-12

o Chief Cells:

Pepsinogen cells

Pepsinogen + HCl = Pepsin (proteinase or polypeptidase)

which produces short peptideso Mucous Cells:

Stomach well endowed with (Brunners gland) which

prevent pepsin from breaking down stomach wall

o Gastrin Cells:

Also known as Endocrine

Produced by stomach which activates gastrin activity

Initiates further secretion of parietal & chief cells

• Glandular Tissue

• Partial Hydrolysis of proteins occurs here

• Stomach is holding organ• Cardiac Sphincter: physiologic constrictor

• Swallow a bolus which enters a stomach

• Chyme: Semi fluid material (food & stomach secretion)

o Short Peptides chains

o Initiate stomach emptying with high peptide content

o 3-5 hours for completion

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Bile salts surround fatty acids & glycerol to form micelles

Micelles pass through epithelium by simple diffusion

Micelle critical structure to epithelial absorption

Within epithelial cell fatty acids & glycerol are converted

to triglycerides; proteins coat triglycerides to form

chylomicrons which move out of intestinal epithelium byexocytosis

Chylomicrons enter lacteals of intestinal villi & are carried

through the lymphatic system to general circulation

Chylomicrons: Taken up by adipose cells & stored or

dismantled by liver

o Amino Acid Transport:

Amino acids are absorbed by secondary active transportinto intestinal epithelial cells

Amino acids move out of intestinal epithelial cells by

active transport

They enter capillaries of the intestinal villi & are carried

through the hepatic portal vein to the liver

G: Liver:

• Accessory digestive organ

• Digestive function: emulsify lipids which prepares them for enzyme

activity

• Produces Bile salts

o Bile stored in Gall Bladder

• Largest internal organ

• Detoxification

H: Pancreas:

• Accessory digestive organ

• Exocrine digestive: contains ducts, Acini gland that produces digestiveenzymes

• Endocrine hormones: contains no ducts, Islets of Langerhan produce

insulin & glucagon

• Pancreatic fluid: Alkaline fluid which neutralizing fluid for enzymes to be

effective

I: Large Intestine:

***Figure 24.25 P.894***

• Larger in diameter but shorter in length than the small intestine• Tenaie Coli:

o Muscle band that runs length of colon

o Contributes to formation of Haustra or pouches

• Haustra: Have partial septa or partitions

• Lining lacks villi but dies have undulation

• Not as Glandular

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• Mass movements: Strong peristaltic contractions

• Digested & Undigested remains enter colon

• Undigested:

o Food that has escaped due to

Lack of enzymes i.e.: lactase

Cellulose: a plant starch that we can not break down Lack of preparation i.e. Poor mastication

Lack of bile

• E. Coli:

o Process feces

o Undigested remain into fecal matter

o Provides us with Vitamin K

• Absorption: Removes H2O & Electrolytes

• Defecation Reflex:

o Stimulated by tactile, chemical & olfaction

o Primary stimulation is the contents in the colono Normal absorption activity influences def. reflex of hard mass

o Figure 24.26 P. 895

The presence of food in the stomach & chime in the duodenum

(small intestine) stimulates mass movement in the colon

Mass movements are integrated by the enteric plexus

They propel the contents of the colon toward the rectum

The presence of feces in the rectum stimulates parasympathetic &

local reflexes that result in defecation

Urinary System Chapter 26:

Nephron

o Organized with in renal pyramid

o Share ducts that enter papilla

o Functional unit of kidney

Nephron Structure

o ***Figure 26.5 p.952***

o Bowman’s Capsule leads to Proximal Tubule (Convolution)

o Descending Convolution to (or limb of) Loop of Henle

o Loop of Henle to Ascending Convolution which completes loop

o Distal Convolution joins the Collecting duct

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Blood Supply

o Figure 26.6 p. 953

o Renal Artery enters kidney

o Extensive Branching

o Afferent arteriole brings blood to Bowman’s Capsule

o Glomerulus: network of capillaries with in Bowman’s Capsule

o Glomerulus converges into Efferent Arteriole

o Efferent Arteriole exits Bowman’s Capsule to form Peritubular Capillaries

o Peritubular Capillaries permits communication between convolutions &

loop of Henleo Vasa Recta; mimics Loop of Henle

o Veinuoles drain peritubular capillaries

o Convergence to Renal Vein which exits the kidney

***Exchange takes place between the tubule & capillaries***

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1. Filtration: Forcing things out of blood to tubule through permeable membrane

2. Reabsorption: Tubule to blood or interstitial space. (Also known as reclaim)3. Secretion: Into tubule to urine.

Filtration Events:

Background:

o Water is the vehicle for filtration which contain electrolytes & nutrients to

be reclaimed, Items not reclaimed: urea nitrogen

1. Initial Event is Glomerular filtration (blood supply):a. Not a selective process

b. Driving force is arterial blood pressure which is approx. 70-75mmHg

c. Forces opposing filtrationi. 30mmHg is due to osmotic pressure (this can vary)

ii. 10mmHg is due to tubular pressure

iii. 10mmHg is due to interstitial pressureiv. 75-50= 25mmHg (GCP) that is now net effective filtration pressure

v. 20-25mmHg produce a filtrate in Bowman’s Capsule

d. Nephric Filtrate is equal to: Blood – Cells & Large Proteins

2. Proximal Convolution:

a. Tubular reabsorption b. Every mechanism is available here

i. Diffusionii. Facilitated Diffusion

iii. Active Transport

iv. Osmosisv. Cytosis

c. Key & critical substances are reclaimed

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d. H2O is reclaimed by osmosis (60-80%)

3. Loop Of Henle:

a. Descending Convolution:i. H2O out

ii. Na in

b. Ascending Convolution:i. Not permeable to H2O

ii. Secrete Na & K

c. ***Overall effect or result is the concentration of filtrate***4. Distal Convolution & Collecting Duct:

a. Hormonal Influence:

i. ADH: From the pituitary which permits H2O reabsorption

ii. Aldosterone: Mineralocorticoid, derived from adrenal gland, which permits the reclaiming of Na & the H2O, follows by osmosis.

b. Secretion of H & K

i. Blood acidosis & dec, in pH response is to secrete H ions into

filtration:ii. CO2 + H2O H2CO3 H + HCO3

5. Summary:a. 60% of Nitrogenous waste remains in filtrate

b. Proximal Convoluted tubule is the most active & use more energy

c. Loop of Henle: There is a relationship with surrounding tissue & VasaRecta.

Respiratory:Ventilation:

Ventilation involves air mass movement by pressure differences

Atmospheric pressure 760mmHg @ sea level Involves Diaphragm & Intercostals

Diaphragm depress’ & ribs elevate: Decrease in intrapulmonary pressure &

Increase in volume inhalation

Diaphragm elevated & ribs depressed: Increase in intrapulmonary pressure &

decrease in volume exhalation

Control:

Respiratory center is in the medulla

Send impulses to intercostals of diaphragm (Phrenic nerve)

Stretch receptors in lung tissue & airways send inhibitory impulses to medullafor exhalation (also known as vagal reflex, over inflation reflex)

Chemo receptors: Located in aorta & carotid arteries

o Elevated Co2 & H, Decreased O2 = Acidosis which will induce

hyperventilation

o Decreased CO2 & H, Increased O2 = Alkalosis which will induce

hypoventilation

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At the Alveolus PO2 is inc & PCO2 is dec

Arteries: PO2 inc & PCO2 dec

Blood entering tissue capillaries is Oxygenated

Body cell: PO2 dec & PCO2 is inc.

Blood leaving tissue capillaries is CO2 enriched

Pulmonary Artery: PO2 dec & PCO2 is inc.

Cl is exchanged for HCO3

Carbonic acid formation is produced by Carbonic anhydrayseOxyhemoglobin is critical to O2 transport

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