PT509 Unit 8

pancreatic

exocrine vs endocrine

hormones

What is a common pathology in the pancreatic system?

diabetes

renal

filtration & reabsorption

acid-base regulation

hormones

What are common pathologies in the renal system?

kidney stones

UTI

CKD

hepatic

energy production

metabolism

detoxification

Where is the location of the pancreas?

posterior to stomach

from duodenum to spleen

What are the dual functions of the pancreas?

exocrine & endocrine

exocrine system function

produces digestive enzymes that are critical for breaking down macronutrients

98-99%

Acinar cells

endocrine system function

1-2%

Islets of Langerhans

releases hormones into blood stream

main pancreatic duct

merges with bile duct, empties into duodenum

proteases

break down proteins

amylase

break down carbohydrates

lipase

break down fats

How is digestion aided after food leaves stomach?

enzymes are secreted directly into the small intestine

How is stomach acid neutralized when entering the small intestine?

pancreas also secretes bicarbonate-rich fluid

bicarbonate

helps maintain a neutral pH

protects intestinal tissues & allows enzymes to function properly

Islets of Langerhans

Beta cells (60-70%) secrete insulin to lessen blood glucose

alpha cells (20-25%) secrete glucagon to increase blood glucose

Islets of Langerhans - beta & alpha cells

work in opposition to maintain homeostasis

What is the primary stimulus for insulin?

glucose

What triggers glucagon release?

hypoglycemia

Islet vascularization

rich capillary network → facilitates rapid hormone delivery to bloodstream

Beta cell synthesis

synthesize proinsulin → cleaved into insulin + C-peptide

What does the secretion of proinsulin trigger?

increase plasma glucose

GLUT2 transporter

increase ATP

closes potassium channels

membrane depolarization

Ca2+ influx

insulin release

glucagon

secreted by alpha cells during fasting or hypoglycemia

hypoglycemia

low blood sugar

What does the secretion of glucagon result in?

decreased plasma glucose

increased amino acids

sympathetic stimulation

What occurs at the liver after glucagon release?

increased glycogenolysis

increased gluconeogenesis

decreased glycolysis

glycolysis

conversion of glucose

What occurs to adipose when glucagon is released?

increased lipolysis → free fatty acids for energy use

type 1 diabetes

autoimmune process attacking the islet cells of pancreas

develops in adolescence

stop producing insulin

genetic markers

absolute insufficiency of insulin

type 1 diabetes

type 2 diabetes

cellular resistance to insulin

usually develops later in life

associated with obesity

hyperglycemia

relative insulin insufficiency

type 2 diabetes

blood glucose level during fasting - normal individual

80-100 milligrams per deciliter

blood glucose level during fasting - impaired glucose individual

101-125 milligrams per deciliter

blood glucose level during fasting - diabetic individual

>126 milligrams per deciliter

A1C

tests average blood glucose for the last 3 months

What are acute symptoms of diabetes?

polyuria

polydipsia

weight loss

increased appetite

polyuria

frequent urination

glucose spilling into urine (carries water molecule)

polydipsia

increased thirst

weight loss in type 1 diabetes

compensates for energy loss

increased appetite in type 1 diabetes

glucose not being absorbed efficiently

What are long term symptoms of diabetes?

large blood vessels (macrovascular) → accelerated atherosclerosis → heart disease

small blood vessels in retina, renal glomerulus, and peripheral nerves → blindness, chronic kidney disease, diabetic neuropathy

impaired wound healing and markedly increased risk for infections

diabetic ketoacidosis

fat is broken down into ketone bodies to uise as energy when there is not enough usable glucose available

What are results of diabetic ketoacidosis?

increased acidity of the blood (decline in body’s pH)

glucose levels are so high in the blood that it draws water out of cells → total body dehydration

increased acidity of the blood - effects

labored breathing

fruity/sweet breath & urine

potassium disturbances

nausea

vomiting

coma

hypoglycemia

low blood glucose <70 mg/dL

dizziness, syncope, seizure, death

overdose of insulin

How does exercise affect diabetes?

key component of the overall intervention

decreases needs for insulin

regulates glucose

increases insulin sensitivity

hypoglycemia in terms of exercise

life or death emergency

immediately provide fast acting carbohydrates

glucose meter for blood glucose test

renal (urinary) system functions

filters blood

regulates fluid volume, electrolytes and acid-base balance

produces important hormones

How does the renal system filter blood?

removes waste

retains nutrients & minerals

How does the renal system regulate fluids?

fluid balance regulation

electrolytes: Na+, K+, Ca2+

blood pressure regulation via renin

How does the renal system produce hormones?

erythropoietin (RBC production)

renin (BP)

active vitamin D

kidneys

paired organs (T12-L3)

connect to bladder via ureters

urine excreted via urethra

What is the gross structure of the kidney?

cortex

medulla

renal pelvis

cortex

OUTER region containing glomeruli and proximal/distal tubes

medulla

INNER region containing loops of Henle and collecting ducts

renal pelvis

collects urine and channels it to the ureter

nephron

functional unit of the kidney

great asset

can sustain nephron/kidney damage

Around how many nephrons are present per kidney?

~1.2 mill

What does it mean to lose nephrons?

lose filtration

nephron components

glomerulus

proximal tubule

loop of Henle

distal tubule

collecting duct

glomerular filtration rate

~180L/day

~1.5 excreted as urine

hard working

What is the tubular reabsorption of nephrons?

proximal tubule

loop of Henle

distal tubule & collecting duct

proximal tubule

reabsorbs ~65% of Na+, glucose, amino acids, water

loop of Henle

creates osmotic gradient for urine concentration

distal tubule & collecting duct

fine-tune water/electrolyte balance via hormones

What are the 2 compensatory mechanisms in acid-base regulation?

acidosis & alkalosis

maintain blood pH

acidosis

pH <7.35

detected by high CO2

high hydrogen, acidic

alkalosis

pH >7.45

detected by low CO2

low hydrogen, basic

What is the respiratory system response to acidosis?

hyperventilation

What is the respiratory system response to alkalosis?

hypoventilation

What is the renal system response to acidosis?

retention of bicarbonate ions

buffers high acidity produced by high hydrogen ions

What is the renal system response to alkalosis?

excretion of bicarbonate ions

H+ retention

renin-angiotensin-aldosterone system

renin (from kidney)

activates angiotensin I (from liver) → angiotensin II

vasoconstriction

increased water & sodium reabsorption

increased systemic blood pressure

angiotensin II → aldosterone (from adrenal cortex) enhances Na & water reabsorption

angiotensin II → antidiuretic hormone

renal absorption of water

erythropoietin

stimulates RBC production (in bone marrow) in response to low O2

vitamin D

2nd step in activation occurs in kidney

Why is RAAS produced?

as am result of blood pressure

detected at kidney

sodium & water retention = stimulates systemic blood pressure

kidney - sympathetic innervation ONLY

regulates renal blood flow, filtration, Na+ reabsorption and renin release

increases systemic blood pressure

sensory (afferent) fibers in kidney

highly sensitive to blood volume & renal blood flow

kidney stones (calculi)

crystalline (4 types) calcium, struvite, uric acid, cystine

varied shape/size, may move into ureter (painful)

fever, chills, sweats, groin/low back pain, hematuria

more common in men

hematuria

blood in urine

urinary tract infection

in bladder, urethra, kidneys

fecal associated gram-negative organisms with E coli accounting for approximately 80%

more common in women due to shorter urethral distance

frequency, urgency, dysuria, nocturia, bloody or foul-smelling urine

altered mental status

chronic kidney disease

eGFR <60ml/min for a duration of >3mos

What are risk factors for chronic kidney disease?

diabetes

hypertension

heart disease

obesity

smoking

prior kidney injury

end stage renal disease

requires dialysis or kidney transplant

What are systemic impacts of chronic kidney disease?

skeletal fracture

pulmonary edema

cardiovascular disease, hypertension

GI bleed

chronic hypertension

primary contributor to organ remodeling & fibrosis

Where is the liver located?

upper right quadrant of the abdomen

(just below the diaphragm)

What are the lobes of the liver?

right (larger)

left

caudate

quadrate

What is the dual blood supply of the liver?

hepatic artery & portal vein

hepatic artery

~25%

oxygen rich blood

portal vein

~75%

nutrient-rich, deoxygenated blood from GI-tract

What is the drainage of the liver?

hepatic veins → inferior vena cava

What are the functions of the liver?

digestive

endocrine

excretory

hematologic

liver and gut

key organs in nutrient absorption and metabolism

What does the liver produce?

albumin

bile

clotting factors

storage of vitamins

What are extra things the liver does?

eliminates toxins from the body

filters all blood from the GI system

gluconeogenesis

glucose synthesis

primarily during fasting

releases glucose into the blood

energetically expensive ~6 ATP

What are the precursors of gluconeogenesis?

lactate & glycerol