VTPP 435 - Final Exam

Understand Energy Balance and basics of basal metabolic rate.

Discuss factors of how food intake is controlled, including the role of the arcuate nucleus of the hypothalamus, ghrelin, PYY, leptin, insulin, and cholecystokinin.

Discuss some of the causes of obesity.

what factors influnce basal metabolic rate

thyroid hormone and epinephrine

what is the majority of food energy converted into in the body?

heat

what is the primary regulatory center of food intake?

hypothalamus

what is the arcuate nucleus?

central role in long-term control of energy balance and body weight and short-term control of food intake from meal to meal

what is the main role of NPY for food intake

appetite stimulator

what is the main role of melancortins for food intake

tone down appetite

what is the imput for the NTS

• higher hypothalamic neurons

• digestive tract (Distension, CCK)

• Diagram the thermal balance for the body, including heat production (metabolism, exercise, shivering) and heat loss (convection, conduction, radiation, and evaporation).

• Identify those mechanisms that shift from heat production to heat loss when environmental temperature exceeds body core temperature.

• Diagram the negative feedback control of body core temperature, including the role of the hypothalamic set point.

• Contrast the stability of body core with that of skin temperature, including the control and mechanisms of cutaneous blood flow and sweating on skin temperature.

• Identify mechanisms for maintaining thermal balance in the following environments: desert (120°F), snow skiing (10°F), falling through ice into a lake (water temp 37°F), and snorkeling in 80°F water.

• Apply surface area to volume ratio to thermoregulation.

• Understand the function and purpose of brown adipose tissue

what is thermoregulation?

being able to maintain an internal core temp even when the surrounding temp is diffrent

what is the thermostat of the body?

hypothalamus

what receptor is stress sweat

alpha 1

what receptor causes constant tone/ vasoconstriction

Alpha 1

• Summarize the functions of the kidneys.

• Describe blood flow through the kidney, including the names of key structures from the renal artery to the renal vein, including the glomerular blood vessels, peritubular capillaries, and the vasa recta.

• Describe the differences between cortical and juxtamedullary nephrons.

• Name the major components of a nephron and identify them on diagram.

• Define and describe the 3 major processes that occur in the nephron.

• Define and describe excretion.

• Describe renal handling of substances with the following properties.

• Include how much of the substance will appear in the urine.

  • Filtration only

  • Filtration and partial reabsorption

  • Filtration and complete reabsorption

  • Filtration and secretion

what are the three main functions of the kidneys

Regulatory (water balance, elecrolyte balance, acid-base balance), Endocrine ( Erythropietin, RAAS, Vit D), and Excretory (waste elimination)

what is the smallest functional unit of the kidney?

the nephron

where does the kidneys get blood from?

the abdominal aorta, 20-22% of output

what is special about the renal blood supply?

portal system (2x capillaries)

what are the vascular components?

• Afferent arteriole

• Glomerulus (1st Cap, job is filtration)

• Efferent arteriole

  • Peritubular capillaries (cartical)

  • Vasa recta (jux nefron)

• Venule

what are the tubular components?

• Tubular components

• Bowman's capsule

• Proximal tubule (the heavy lifter)

• Loop of Henle (active and passive reabsorption)

  • Descending limb

  • Ascending limb

  • Thick and thin portions

• Distal tubule/Collecting ducts (This is where we have regulation)

what is glomerular filtration?

nondisciminant filtration of a protien free plasma from the glomerulus into bowman’s capsule

what is tubular reabsorption?

selective movement of filtered substances from the tubular lumen into the peritubular capillaries

what is tubular secretion

selective movement of nonfiltered substances from the peritubular capillaries into the tubular lumen

how much plasma gets filtered per minute

20% so 125mL per min, 180 L per day

how much do we excrete from the kidneys?

1 mL per min, 1.5 L/day

• Name the major components of the filtration barrier and the properties of each.

  • How do these properties affect filtration?

• Define glomerular filtration rate (GFR).

• Given the capillary and Bowman's capsule hydrostatic and oncotic pressures, calculate the net filtration force at the glomerular capillaries.

  • Predict the changes in glomerular filtration caused by increases or decreases in any of those pressures.

• Compare the composition of filtrate in Bowman's capsule to plasma.

• Describe the factors that affect glomerular filtration rate.

• Predict the change to GFR with an increase or decrease in any of these factors.

• Explain the effect on GFR when afferent or efferent arteriolar resistance is increased.

filtration of blood in the nephron…

is based on size and charge

what part of the nephron is the fenestrated endothelium?

the glomerulus (very very peramble)

what do cells in the fenestrated endothelium have

the glycocalyx

what is the basement membrane compsed of fro the gloerular filtration barrier?

acellular glycoprotiens

where are the podcytes with filtration slits located?

bowman’s capsule

what is the glomerular Filtration Rate dependent on?

Filtration Pressures and Filterability

what are the glomerular filtration pressures?

• Glomerular Capillary Blood Pressure (55 mm Hg) - Favors

• Plasma-colloid osmotic pressure (30 mm Hg) - opposes

• Bowman's capsule hydrostatic pressure (15 mm Hg) - opposes

Net filtration pressure = 55 - 30 - 15 = 10 mm Hg - favors

Why does colloid oncotic pressure increase from the afferent end to the efferent end?

you’re losing water

Describe the steps in the Renin-Angiotensin-Aldosterone System (RAAS). Include descriptions of stimuli that trigger the system, the active components of the system, and the end results from activating this system.

Explain what leads to the release of ANP/BNP, their mechanisms of action and the net result.

Explain tubular (transport) maximum and renal threshold and filtered load.

Describe how glucose is handled in the kidney.

Discuss the role of the kidney in regulating blood glucose.

Define osmosis and explain how water reabsorption in the kidney occurs.

Characterize urea handling in the kidney.

what is the majority of the energy used by the kidneys used for?

Na+/K+ ATP on the basolateral membrane

where do we reabsorb the majority of sodium?

the proximal tubule

where ca we regulate sodium reabsoption

the distal and collecting tubules

what would trigger activation of RAAS

a decrease in BP

what is the starting renal threshold

300 mg/100ml

what is the GFR constant?

125 ml/min

what are the reabsopton formulas

Filtered Load – Reabsorbed = Excreted

([plasma]*GFR) – Reabsorbed = Excreted