28. Muscles, adipose tissue, kidneys and brain

Question 1

Explain a muscle contraction:

Answer 1

-

Question 2

What does myofilaments build and what are they build up by?

Answer 2

Myofiber –> myofibril (contractile) –> myofilaments (proteins which are contractile: Actin and myosin, proteins which are regulatory: tropomysin and troponin.)

Question 3

what happens if Ca concentration increase?

Answer 3

It binds to troponin=tropomyosin are changed and cross bridge can happen.

Question 4

Types of energy:

Answer 4

-Creatine-P -FA -ATP -Glucose (aerobe, anaerobe)

Question 5

Types of muscle fibers:

Answer 5

Red, type 1, it contains more mitichondrias and has more oxidative phosphorylation = more O2, red arteries. White type 2.

Question 6

Typical for white muscle fibers:

Answer 6

Fast contraction, fast twitch (conduction), anaerobe respiration, short duration contraction, fast fatique, example: pectorals, gastrocnemius.

Question 7

Typical for red muscle fibers:

Answer 7

slow contraction (because of many processes), slow twitch (conduction), aerobe respiration, long duration contraction, slow fatique, example: Gluteus, which we use everyday.

Question 8

Muscle types:

Answer 8

-Skeletel, long and multinucleus. -Cardiac (FA energy) -Smooth

Question 9

Adipose tissue:

Answer 9

Adipose tissue, body fat, or simply fat is a loose connective tissue composed mostly of adipocytes. - In addition to adipocytes, adipose tissue contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular endothelial cells and a variety of immune cells such as adipose tissue macrophages. - Its main role is to store energy in the form of lipids, although it also cushions, insulates the body and protects organs.

Question 10

Types of adipose tissue:

Answer 10

The two types of adipose tissue are white adipose tissue (WAT), which stores energy, padding and heat generation. -Brown adipose tissue (BAT), which generates body heat for new borns, hibernating animals, it has a lot of mitochondrias.

Question 11

Explain thermogenin:

Answer 11

Thermogenin (called uncoupling protein by its discoverers and now known as uncoupling protein 1, or UCP1, is an uncoupling protein found in the mitochondria of brown adipose tissue (BAT). It is used to generate heat and makes a quantitatively important contribution to countering heat loss in babies and hibernating animals which would otherwise occur due to their high surface area-volume ratio.

Question 12

Renal functions:

Answer 12

-Electrolyte & Fluid Balances -Acid-Base Balances -Elimination of Metabolic Wastes -Blood Pressure Regulation -Endocrine functions: Vitamin D Synthesis -Red Blood Cell Production -Prostaglandins Synthesis

Question 13

How is glucose transported to the kidney?

Answer 13

Sodium-glucose linked transporter, SGLT. Glucose transporter found in the intestinal mucosa (enterocytes) of the small intestine (SGLT1) and the proximal tubule of the nephron (SGLT2 in PCT and SGLT1 in PST). -They contribute to renal glucose reabsorption. In the kidneys, 100% of the filtered glucose in the glomerulus has to be reabsorbed along the nephron (98% in PCT, via SGLT2). - If the plasma glucose concentration is too high (hyperglycemia), glucose is excreted in urine (glucosuria) because SGLT are saturated with the filtered glucose. Glucose is never secreted by a healthy nephron.

Question 14

Is there any storage in the kidney?

Answer 14

A small glycogen storage

Question 15

GLUT2:

Answer 15

Glucose transporter 2 (GLUT2) also known as solute carrier family 2 (facilitated glucose transporter), member 2 (SLC2A2) is a transmembrane carrier protein that enables protein facilitated glucose movement across cell membranes. Unlike GLUT4, it does not rely on insulin for facilitated diffusion.

Question 16

Synthesis happening in the kidney:

Answer 16

GNG, GL, ketolysis, Beta ox

Question 17

Synthesis happening in adipose tissue:

Answer 17

FA–>Beta ox, lipolysis, glycolysis, ketolysis

Question 18

Biochemistry of the brain:

Answer 18

No storange, 2% of mass, glucose is very important for the brain, it can cross the blood brain barrier. If it does not get glucose for a few minutes you will be in a coma. During starvation, ketone bodies can be used as fuel. High O2 supply.

Question 19

GLUT4

Answer 19

GLUT4 is the insulin-regulated glucose transporter found primarily in adipose tissues and striated muscle (skeletal and cardiac). At the cell surface, GLUT4 permits the facilitated diffusion of circulating glucose down its concentration gradient into muscle and fat cells. Once within cells, glucose is rapidly phosphorylated by glucokinase in the liver and hexokinase in other tissues to form glucose-6-phosphate, which then enters glycolysis or is polymerized into glycogen. Glucose-6-phosphate cannot diffuse back out of cells, which also serves to maintain the concentration gradient for glucose to passively enter cells.

Question 20

GLUT in the brain:

Answer 20

Glucose delivery and utilization in the mammalian brain is mediated primarily by GLUT1 in the blood–brain barrier, GLUT3 in neuronal populations and a less glycosylated form of GLUT1 in the remainder of the parenchyma. GLUT3 is considered the main but not the exclusive neuronal glucose transporter, whereas other glucose transporters have also been observed in neurons.

Question 21

Source of ATP used for muscle contraction

Answer 21

Question 22

Compare red, white and intermediate and cardiac muscle (fibers):

Answer 22