Physiology Midterm Lecture #1 Flashcards Preview

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Flashcards in Physiology Midterm Lecture #1 Deck (49)
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1
Q

Summation

A

the process of adding up postsynaptic potentials and responding to their net effect
(Occurs in the trigger zone)

2
Q

Temporal summation:

A

occurs when a single synapse generates EPSPs so quickly that one is generated before other one fades

3
Q

Spatial summation

A

occurs when EPSPs from several different synapses add up to threshold at an axon hillock

4
Q

Presynaptic Inhibition

A
  • releasesGABA

Prevents voltage-gated Ca2+ channels in synaptic knob (S) from opening and so little or no neurotransmitter is released

5
Q

Functions of the Skeleton

A
  1. Support
    2.Protection
  2. Movement
  3. Electrolyte balance
    – calcium and phosphate levels
  4. Acid–base balance
    6.Blood formation
6
Q

Osteogenic cells

A

tem cells that give rise to most other types of bone cells

7
Q

Osteoblasts

A

bone forming cells

– Found under the endosteum and periosteum on the bone surface

8
Q

Osteocytes

A

osteoblasts that have become trapped in the matrix they deposited
Lacunae cavities where osteocytes reside
Canaliculi–channels connecting lacunae

9
Q

Physiology of Osseous Tissue

A
  • Metabolically active
  • phosphorous
  • calcium
10
Q

Mineral Deposition (mineralization)

A
  • Crystallization process
  • Calcium, phosphate, and other ions are taken from blood and deposited in bone - hydroxyapatite
  • osteoblast
11
Q

Mineral Resorption

A

process of dissolving bone and releasing minerals into blood

-osteoclast

12
Q

Hypocalcemia

A

deficient calcium in blood
- results in changes in membrane potentials (muscle spasms)
this is caused by vitamin D deficiency

13
Q

Hypercalcemia

A
  • excessive calcium levels results ion channels less responsive
14
Q

What Parathyroid hormones maintain norm blood calcium concentration?

A

Calcitriol (most active from is VD) and calcitonin

15
Q

Calcitriol raises blood by

A

increase of Ca by the small intestine
increases Ca by skeleton
kidney reabsorption of Ca

16
Q

Calcitonin decreases blood by

A

secreting C cells of thyroid glands

17
Q

Homeostasis

A

the ability to detect change,activate mechanisms that oppose it, and thereby maintain relatively stable internal conditions

18
Q

Claude Bernard (1813–78)

A

Noted fairly constant internal conditions

19
Q

Walter Cannon (1871–1945)

A

Coined the term homeostasis

20
Q

Negative Feedback

A

allows for dynamic equilibrium within a limited range around a set point

21
Q

Heat-losing Mechanism

A

If too warm, vessels dilate in the skin and sweating begins

22
Q

Heat-gaining mechanism

A

If too cold, vessels in the skin constrict and shivering begins

23
Q

Homeostasis
Receptor
Integrating center
Effector

A

Receptor– structure that senses change in the body

Integrating (control) center– processes the sensory information, “makes a decision,” and directs the response

Effector
– cell or organ that carries out the final corrective action to restore homeostasis

24
Q

Positive Feedback and Rapid Change

A

loop causes a self-amplifying cycle where a physiological change leads to even greater change in the same direction
birthing

25
Q

Nervous system communication:

A

communicates by electrical and chemical means to send messages from cell to cell

26
Q

Endocrine system communication:

A

communicates by means of chemical messengers (hormones) secreted into to the blood

27
Q

CNS

A

Brain and spinal cord
– Enclosed by cranium and vertebral
column

28
Q

PNS

A

all other nerves besides brain and spinal cord

29
Q

Nerve

A

a bundle of nerve fibers(axons)

wrapped in fibrous connective tissue

30
Q

Ganglion

A

a knot-like swelling in a nerve where neuron cell bodies are concentrated

31
Q

Sensory (afferent) Division of the PNS

A

Carries signals from receptors to CNS

Somatic - carries signals from skin, muscles, joints

Visceral - “” heart, lungs

32
Q

Motor (efferent) division of the PNS

A

carries signals from CNS to effectors
Somatic - ‘’ skeletal muscles
Visceral - carries signals to glands, cardiac and sm

33
Q

Properties of a Neuron

A

Excitability- ability to respond to a stimuli

Conductivity- produce electrical signals to other cells

Secretion - secretes a neurotransmitter

34
Q

Dendrites:

A

Primary site for receiving signals from Nucleus other neurons

35
Q

Soma:

A

control center of neuron – aka cell body

36
Q

Axon (nerve fiber)

A

Specialized for rapid conduction of signals to distant points

37
Q

Synaptic knob (terminal button):

A

junction (synapse) with the next cell

38
Q

Myelin Sheath

A

Formed by oligodendrocytes in CNS and Schwann cells in PNS

39
Q

Electrophysiology

A

study of cellular mechanisms for producing electrical potentials and currents

40
Q

Electrical Potential

A

a difference in concentration of charged particles between one point and another

-cells are polarized, more negative on the inside of the membrane than outside

41
Q

Electrical Current

A

a flow of charged particles from one point to another

42
Q

Resting Membrane Potential

A

due to the unequal distribution of ECF and ICF

  1. Ions diffuse down their concentration
    gradient
  2. Plasma membrane is selectively permeable
  3. Electrical attraction of cations (+) and anions (-) to each other
43
Q

Characteristics of Actions potentials

A
  1. All or None
  2. Nondecremental - does not get weaker with distance
  3. Irreversible
44
Q

Refractory Period

A

a few ms after it is difficult or impossible to stimulate that region. The period of resistance to restimulation

45
Q

Absolute refractory period

A

no stimulus of any strength will trigger AP

last as long as inactivated Na+ gates are closed

46
Q

Relative refractory period

A

Only very strong stimulus will trigger new AP,

last until hyper-polarization ends

47
Q

Saltatory Conduction

A

signal seems to jump from node to node

48
Q

Speed Conduction of Nerve Fibers

A

Diameter of fiber - large fibers have increased SA = more rapid signals

Myelin = faster signal conductions

49
Q

What ions are more abundant inside and outside the cell?

A

K+ concentration is higher inside the cell

Na+ is higher outside the cell