Thermoregulation + BMR

98.6 is equivalent to 100.4 is equivalent to 104 is equivalent to

37 C38 C40C

What temp is someone febrile?

100.4 F

How is body temp controlled?

Balancing heat production against heat loss

Extra rate of metabolism is caused by?

-Muscle activity-Thyroxine-Epinephrine, norepinephrine-Increase chemical activity of cells-Metabolism

Which tissues work together to act as a heat insulator?

-Subcutaneous tissues-Skin

In cold temps, there is a

low rate of skin flow

What are the 4 types of heat loss?

-Radiation-Conduction-Convection-Evaporation

What is conduction?

Transfer of heat thru physical contact, kinetics

Convection

Removal of heat from body by air current

Radiation

Loss of heat in form of infrared heat rays, naked person will lose 60% of total heat by radiation

Is rate of heat loss to water greater or lesser than the rate of heat loss to air?

Greater

Evaporation

Loss of heat when H2O evaporates from body surface

2 types of sweat glands

apocrine: Androgenseccrine: Somatic Nervous System

If temp of surroundings is greater than skin temp, body gains heat by

RadiationConduction

What is the only way of heat loss if temp of surrounding is greater than skin temp?

Evaporation

Which 3 organs systems are responsible for heat loss?

-Skin-Cardiovascular-Respiratory

What do heat sensitive cells do?

-Induce sweating-Vasodilation-Decrease heat production (inhibit shivering)

What do cold sensitive cells do?

-Piloerection-Vasoconstriction-Increase in heat production (Shivering, thyroxine)

Predisposing factors of hyperthermia

-Age of pt-Type 1 DM-Diuretics-Beta blockers:vasodilation-Psychotropics-Level of acclimation-Length + intensity of exposure-Env. factors: humidity + wind

heatstroke

Critical organ damageMortalityBody temp > 105F

How to treat heat cramps?

-Cooling measures-Fluid-Electrolytes

signs of heat exhaustion

-Nausea-Vomiting-Lightheadedness-Minimal altered mental status

Signs of heatstroke

-Confused-Agitated-Tachycardia-Tachypnea-Decrease in BP

Exertional vs Classic Heatstroke

Exertional: younger, fit pt, not dehydrated, has elevated body temp (organs) Classic: Exposed to sig. temps over hours/days, sweat a lot and very dehydrated

Treatment of heatstrokes

-ABC's-Prevent shivering-NPO-Fluid bolus-IV-Anticipate seizures: treat w/ Diazepam-High mortality

Hypothermia

Core temp. less than 95F

Heat generated by cell metabolism through which 2 organs?

Heart + Liver

MILD Hypothermia symptoms

-Tachypnea-Tachycardia-Hyperventilation-Impaired judgement -Ataxia: poor muscle control-Dysarthria: slurred speech-Increased urination (cold diuresis)

Why does cold diuresis occur?

-Way to preserve heat-

MODERATE hypothermia

-Bradycardia-Decreased cardiac output-Hypoventilation-A-Fib-Junctional Bradycardia + other arrythmia-Decreased renal blood flow -Paradoxical undressing-CNS depression, hyporeflexia-muscles less responsive to stimuli

SEVERE hypothermia

-Pulmonary edema-Oliguria- low urine output-Areflexia- muscles don't respond to stimuli-Coma-Hypotension-Bradycardia-Asystole-V dysrhythmia

Hypothermia management

-Warm blankets-Radiant heat-Warm bath-Warm trunk 1st + minimize use of peripheral muscles

Which tests to run w/ Hypothermia?

-Electrolytes-Hematocrit-Coag studies-ABGs (Arterial Blood Gas) EKG

Treatment of Hypothermia Induced Dysrhythmia

-A-fib + flutter resolve w/ rewarming, try this before med -Management of V-fib + Asystole is difficult, have to warm pt to core temp 1st

A hypothermic heart is

-Very sensitive to movement, rough handling could lead to dysrhythmia

Metabolic rate

Energy spent per unit of time

Factors that influence metabolic rate

-Exercise-Food intake-Shivering-Anxiety

Factors that influence BMR

-Food intake-Thyroid hormone-Activity level-Age

Basal metabolic rate (BMR)

Minimal rate of energy spent by endothermic animals at rest

Glycogenesis

glucose to glycogen

Glycogenolysis

breakdown of glycogen to glucose

Gluconeogenesis

production of glucose in the liver using fats and proteins

protein syntheis

creation of proteins by cells that uses DNA, RNA

protein degradation

the splitting of proteins by hydrolysis of the peptide bonds, with the formation of smaller polypeptides.

fat synthesis

Creation of fatty acids from acetyl CoA thru fatty acid synthesis

fat breakdown

fatty acids broken down to metabolites, generates Acetyl CoA

Pancreas produces

2 antagonistic hormones to control blood sugar:-Insulin -Glucagon

How does insulin play a role in blood sugar?

-Beta cells produce insulin which:-Facilitate glucose entry into cells -Stimulates Glycogenesis-Inhibits Glycogenolysis-Inhibit Gluconeogenesis

How does insulin play a role in fat?

-Increase transport to adipose tissue-Promote protein synthesis-Inhibit protein degradation

Insulin play a role on protein

-Promote uptake of amino acids-Promote protein synthesis-Inhibit protein degradation

glucagon comes from

alpha cells of pancreas

What does glucagon do?

Raises blood glucose levels by making liver metabolize glycogen into glucose

What do epinephrine, cortisol + growth hormone do?

Increase glucose + fatty acids

WHat does cortisol do?

Increase blood amino acids + decrease muscle protein

What does growth hormone do?

decrease blood amino acids + increase muscle protein

Calorie

the energy needed to raise the temperature of 1 gram of water through 1 °C

What are the final products of carbohydrate digestion?

-Glucose--> most-Fructose-Galactose

By what process does the liver store glucose as glycogen?

Glycogenesis

Which organs does Epinephrine work on?

Liver + Skeletal muscle

Where does Glycogenolysis take place?

Liver + Skeletal muscle

What stimulates Gluconeogenesis?

Serum glucagon levels

How are fats in diet absorbed into intestinal lymph by?

Chylomicrons

How are chylomicrons removed from blood in adipose tissue + liver?

Lipoprotein lipase

What can thyroid hormone do in fat metabolism?

Cause rapid mobilization of fat

What does growth hormone do?

-Increase synthesis of cellular protein-Decrease glucose release + use fatty acid for energy

What do Glucocorticoids do?

-Decrease proteins in tissue

What does testosterone do?

-Increase protein in tissue

BMI <18 is 18-24 is25-29 is30-39 is>39 is

-Underweight-Healthy/optimal-Overweight-Obese-Extremely obese

If skin temp is > temp. of surroundings, heat is lost via

radiation, conduction + convection

If temp of surroundings is > skin temp., body can only lose heat via

Evaporation