The internal environment is in direct contact with the body’s cells and consists of the extracellular fluid An electrical gradient is a difference in charge between two adjacent areas that promotes movement of ions toward an area of opposite charge Pinocytosis is a form of endocytosis in which small particles are brought into the cell, forming an invagination, and then suspended within small vesicles
Individual proteins typically pass through the plasma membrane by simple diffusion via the protein channel
Extracellular fluid is the internal environment of the body, is outside the cells but inside the body, consists of the plasma and interstitial fluid, and exhibits a dynamic steady state in regard to composition, temperature, and volume Which sequence represents a correct hierarchy of biological organization in a human, from smaller to larger? Cell, tissue, organ, system, organism
When is a plasma membrane more permeable to K+ than to Na+?
Development of a resting membrane potential: More K+ ions diffusing into the cell than there are Na+ ions diffusing out of the cell
The resting membrane potential of a typical nerve cell is -70 mV
Resting membrane potential: It is closer to the equilibrium potential for K+ than to the equilibrium potential for Na+. It is about the same as the equilibrium potential for Cl-.
Na+ entering the cell causes depolarization
K+ leaving the cell causes repolarization Water reabsorption is under the control of vasopressin or ADH -- BOTH
Graded potentials fire according to the stress or stimulation
A threshold potential is the point at which many sodium voltage-gated channels open simultaneously.
A change in a membrane potential from +30 mV to -70 mV is an example of REPOLARIZATION
Which statement(s) is/are true about membrane potentials? They are differences in electrical charge on opposite sides of a membrane
Which of the following is reabsorbed by the proximal tubule? Sodium, amino acids, and glucose
In most excitable cells, the rising phase of the action potential is due to the Na+ volatage-gated channels being open and K+ voltage-gated channels being closed
An action potential on a neuron develops when the stimulus is sent down the axon away from the cell body Opening a sodium channel when the membrane potential is at equilibrium will cause DEPOLARIZATION
Sequence the following events correctly in synapse.
1. Sodium flows into the terminal of the presynaptic neuron
2. Calcium flows into the terminal of the presynaptic neuron
3. Neurotransmitter is released by exocytosis
4. Neurotransmitter combines with protein receptor sites on the postsynaptic neuron
5. The permeability of the postsynaptic neuron is altered Exocytosis of secretory products from neuron terminals is triggered by the entry of Ca2+ into the cell in response to a specific neural or hormonal stimulus
The renal process whereby substances are selectively transferred from the peritubular blood into the renal tubule is SECRETION
Which of the following is least related to the juxtaglomerular apparatus? Glomeruli located in medulla
Most related: Long loops of Henle, Peritubular capillaries forming vasa recta, Collecting duct in medulla, Important role in the ability of the kidneys to produce urine of varying concentration The Na+-K+ ATPase transport system that plays a pivotal role in tubular reabsorption is located in the basolateral membrane of tubular cells Aldosterone stimulates K+ secretion in the distal tubule, increases sodium reabsorption into bloodstream, increases water reabsorption, increases blood pressure
Increases blood pressure in the distal tubule
Low blood pressure is sensed by baroreceptors in juxtaglomerular apparatus
Cells of JGA secrete renin into afferent arteriole