Question

how do capillaries resist transport of molecules into the brain?
A. cells lack intercellular pores
B. brain cell membranes resist diffusion
C. inter cranial cells lack mechanisms of active transport
D. endothelial cells are connected by tight junctions.

There is more than one answer

Answer 1

@RamiroCruzo @toxicsugar22 @Rushwr

Answer 2

The blood–brain barrier (BBB) is a highly selective permeability barrier that separates the circulating blood from the brain extracellular fluid (BECF) in the central nervous system (CNS). The blood–brain barrier occurs along all capillaries and consists of tight junctions around the capillaries.

Tight junctions encircle the cell and attach it tightly to its neighbors, these junctions act as a barrier preventing molecules from diffusing across an epithelial sheet between adjacent cells. Tight Junctions have numerous small circular pores.

So, now your correct options should be:

B. brain cell membranes resist diffusion
D. endothelial cells are connected by tight junctions.

Answer 3

@fflloowweerrchilldd ???

Answer 4

thank you so much. can i ask you more questions?

Answer 5

Any time ;)

Answer 6

heart contractions result from the electrical coordination of cardiac muscles through?
A. somatic motor neurons
B. autonomic sensory neurons
C.gap junctions

Answer 7

Autonomic sensory neurons

Answer 8

Happy to see u help @RamiroCruzo ...could you please attach a sufficient reason along with your answer? Thank you!

Answer 9

Oki Doki....... @shreehari499

Answer 10

I'll explain as I know.
Gap junctions are specialized intercellular connections. They allows various ions, molecules and electric impulses to directly pass through a regulated gate between cells.
So we can take that answer out.
So we are left with autonomic and somatic neurons.

Answer 11

So that leads us to choose autonomic motor neuron.

Answer 12

Just think if we were left with somatic motor neuron and the autonomic motor neuron.
Still we should go with the autonomic motor neuron

Answer 13

somatic motor neurons transmits signals to voluntary muscles like striated muscles.
autonomic motor neuron transmits to involuntary muscles like smooth and cardiac muscles and glands.

Answer 14

Did u get it @fflloowweerrchilldd and @toxicsugar22

Answer 15

yeah but thats not the correct answer according to my test

Answer 16

hmm wait try gap junctions then because they allow the transmit of electrical pulses through various photos.

Answer 17

gates not photos lol sorry about that.

Answer 18

okay thank you!

Answer 19

do you mind if i ask any more questions?

Answer 20

yeah yeah