Module 2 Flashcards
(400 cards)
1
Q
What is the role of cell signalling in multicellular organisms?
A
Cell signalling is crucial for the coordination of complex responses, distinguishing animals from other life forms.
2
Q
Which organisms exemplify effective cell signalling?
A
Cephalopods, showcasing rapid environmental responses through chemical pathways.
3
Q
What is the central concept of cell signalling related to maintaining balance in the body?
A
Homeostasis.
4
Q
Why is understanding the solubility of signalling factors important?
A
It is essential for grasping their functions and mechanisms.
5
Q
What are the two categories of signalling factors based on solubility?
A
Hydrophilic (water-soluble) and hydrophobic (fat-soluble).
6
Q
How do hydrophilic signalling factors behave in the body?
A
They dissolve in aqueous environments, can be stored in vesicles, and are rapidly released upon stimulation.
7
Q
What is the release mechanism for hydrophobic signalling factors?
A
They are lipid-soluble, cannot be stored, and are released immediately upon synthesis.
8
Q
How do hydrophilic and hydrophobic factors differ in transport?
A
Hydrophilic factors travel freely in extracellular fluid, while hydrophobic factors require carrier proteins for transport.
9
Q
What is the action mechanism of hydrophilic factors at target tissues?
A
They bind to membrane receptors, triggering intracellular signalling cascades.
10
Q
How do hydrophobic factors influence gene expression?
A
They act as transcription factors, directly influencing gene expression.
11
Q
What are common examples of hydrophilic signalling factors?
A
Proteins such as insulin, glucagon, and prolactin.
12
Q
What characterizes hydrophobic signalling factors?
A
They include steroids, which are synthesized from precursors and released immediately upon production.
13
Q
What is the distinction between hormones and signalling factors?
A
Hormones specifically refer to factors that travel through the bloodstream, while ‘factors’ encompasses a broader range of chemical signals.
14
Q
Give examples of local acting factors that are considered signalling factors but not hormones.
A
Acetylcholine and histamine.
15
Q
What are the six key steps in the endocrine signalling pathway?
A
Synthesis, secretion, transport, binding, signal transduction, and response.
16
Q
Where does hormone synthesis occur?
A
In endocrine glands.
17
Q
What happens to hormones after synthesis?
A
They are secreted into the bloodstream or extracellular fluid as ligands that bind to receptors.
18
Q
What occurs during signal transduction in endocrine signalling?
A
The receptor changes shape upon ligand binding, leading to downstream effects such as enzyme activation or gene expression changes.
19
Q
How is hormone synthesis controlled?
A
It is influenced by the chemical nature of the hormone; proteins are synthesized based on gene expression.
20
Q
What is the release mechanism for hydrophilic hormones?
A
They are stored in vesicles and released via exocytosis.
21
Q
Why is the regulation of hormone synthesis and secretion vital?
A
It is crucial for maintaining homeostasis and responding to physiological changes.
22
Q
What are the two classifications of hormones based on their structure?
A
Hormones are classified as either proteins or chemical products of biosynthetic pathways.
23
Q
How are hydrophilic hormones secreted from cells?
A
Hydrophilic hormones are secreted via vesicles through exocytosis, requiring the endoplasmic reticulum (ER) and Golgi apparatus for intracellular sorting.
24
Q
Where does the synthesis of hormones like epinephrine occur?
A
The synthesis of hormones like epinephrine occurs in the endoplasmic reticulum (ER).
25
What triggers the release of hormones from cells?
The release of hormones is triggered by signals that prompt vesicles to fuse with the cell membrane.
26
How do hydrophobic hormones circulate in the bloodstream?
Hydrophobic hormones require transport proteins, such as albumin and globulins, to circulate in the bloodstream.
27
What is the role of transport proteins for hydrophobic hormones?
Transport proteins bind to hydrophobic hormones, protecting them from degradation and regulating their availability to target tissues.
28
What occurs when a hormone binds to its receptor?
The binding of a hormone to its receptor induces a conformational change that affects the receptor's function and interaction with other proteins.
29
Where can hormone receptors be located?
Hormone receptors can be located on the cell membrane or within the cell.
30
What is the importance of hormone-receptor specificity?
The specificity of hormone-receptor interactions is crucial as receptors are designed to bind only to their corresponding ligands.
31
How can cells adjust their sensitivity to hormones?
Cells can adjust their sensitivity by altering the number or type of receptors they express.
32
What are phytoestrogens and how do they affect hormonal signaling?
Phytoestrogens are plant-derived compounds that resemble estrogens and can interfere with hormonal signaling in vertebrates.
33
What types of receptors are involved in hormone signaling?
Examples of hormone receptors include steroid hormone receptors (e.g., testosterone) and ion channel receptors (e.g., acetylcholine receptor).
34
What role do G-Protein Coupled Receptors (GPCRs) play in hormone signaling?
GPCRs interact with G-proteins to transmit signals from the receptor to intracellular targets, amplifying the response.
35
What is the significance of signal transduction pathways in hormonal signaling?
Signal transduction pathways initiate a signaling cascade, often involving phosphorylation of relay molecules and activation of protein kinases, leading to amplified cellular responses.
36
What is an example of antagonistic hormones and their function?
Insulin and glucagon are antagonistic hormones that have opposing effects on blood glucose levels.
37
What is the role of insulin in blood glucose regulation?
Insulin decreases blood glucose by promoting glucose uptake in muscle cells.
38
How does glucagon affect blood glucose levels?
Glucagon increases blood glucose by stimulating glucose production in the liver.
39
What is the significance of the balance between insulin and glucagon?
The balance is essential for maintaining homeostasis and ensuring proper metabolic function.
40
What happens to insulin and glucagon levels after a meal?
After a meal, insulin levels rise to enhance glucose uptake, while glucagon levels drop.
41
What are tropic hormones?
Tropic hormones regulate the secretion of other hormones and influence multiple endocrine glands.
42
Give examples of tropic hormones.
Examples include Follicle Stimulating Hormone (FSH) and Adrenocorticotropic Hormone (ACTH).
43
What does the term 'tropic' indicate in relation to hormones?
The term 'tropic' means 'to turn', indicating their role in directing hormonal activity.
44
What is the function of the hypothalamus in the endocrine system?
The hypothalamus integrates signals and regulates homeostasis through hormone release.
45
What are the two sections of the pituitary gland and their communication methods?
The anterior pituitary receives signals via portal vessels, while the posterior pituitary releases hormones directly from hypothalamic axons.
46
What is the hypothalamus-pituitary (HP) axis?
The HP axis is crucial for controlling various physiological processes through hormone signaling.
47
What are the adrenal glands and their primary functions?
The adrenal glands are involved in stress response and metabolism regulation.
48
What hormones does the adrenal medulla secrete?
The adrenal medulla secretes epinephrine for immediate 'fight or flight' responses.
49
What does the adrenal cortex produce?
The adrenal cortex produces steroid hormones.
50
What is the HPA axis?
The Hypothalamic-Pituitary-Adrenal axis illustrates the interaction between the hypothalamus, pituitary, and adrenal glands during stress.
51
What is the role of gonadotropin-releasing hormone (GnRH)?
GnRH stimulates the anterior pituitary to release FSH and LH.
52
How do FSH and LH affect hormone production in females?
In females, FSH and LH promote estradiol production.
53
How do FSH and LH affect hormone production in males?
In males, FSH and LH stimulate testosterone production.
54
What are primary and secondary sexual characteristics?
They are developed due to the divergence in hormone production between males and females.
55
What challenges exist in understanding endocrine pathways?
The complexity of hormonal signaling and the vast number of hormones and their interactions can make understanding challenging.
56
What should one focus on when studying hormonal signaling?
Focus on generalized concepts rather than memorizing every hormone; consider the plasticity of signaling pathways.
57
What are some recurring themes in hormonal signaling?
Signaling cascades, receptor interactions, and antagonistic hormone actions.
58
What are neurons?
Specialized cells that transmit signals throughout the body.
59
What is the structure of a neuron?
A neuron consists of a cell body (soma), dendrites, and an axon.
60
What is the function of dendrites in a neuron?
Dendrites are extensions that receive signals from the environment and detect ligands that influence ion channel activity.
61
What is the role of the axon in a neuron?
The axon transmits electrical impulses away from the cell body to other neurons or target cells.
62
How does a neuron differ from a nerve?
A neuron is a single cell, while a nerve is a bundle of many neurons, often with supporting cells.
63
What does it mean for neurons to be excitable cells?
Excitable cells can rapidly change their membrane potential in response to stimuli.
64
What is the process of signal transmission in neurons?
It involves the generation of action potentials and synaptic transmission, where signals are sent from one neuron to another.
65
What occurs in the cell body of a neuron?
The cell body integrates signals received from multiple dendrites to determine the output signal.
66
What are interneurons?
Neurons that connect different neurons, facilitating communication within the nervous system.
67
What is the function of motor neurons?
Motor neurons transmit signals from the central nervous system to muscles, enabling movement.
68
What do sensory neurons do?
Sensory neurons detect stimuli from the environment and relay this information to the central nervous system.
69
What is membrane potential?
The electrical gradient across a cell membrane, essential for cellular function.
70
What is the resting membrane potential of a typical neuron?
Approximately -70 mV, indicating that the inside of the cell is negatively charged relative to the outside.
71
What does polarization mean in the context of membrane potential?
Polarization occurs when the membrane potential is not zero; a polarized cell has a membrane potential that is either positive or negative.
72
What is the role of the sodium-potassium pump?
It maintains the concentration gradients of Na+ and K+ across the membrane.
73
What are the components of the electrochemical gradient?
The chemical gradient (concentration differences) and the electrical gradient (membrane potential).
74
Where is sodium (Na+) more concentrated?
Outside the cell.
75
Where is potassium (K+) more concentrated?
Inside the cell.
76
What happens when ion channels open for Na+?
Na+ moves into the cell due to both the chemical and electrical gradients.
77
What is the equilibrium potential for sodium?
Approximately +40 mV.
78
What is the equilibrium potential for potassium?
About -90 mV.
79
What influences the direction of ion movement in neurons?
The balance of ion gradients.
80
What are action potentials?
Rapid, transient changes in membrane potential that occur when a neuron is sufficiently stimulated.
81
What is the first phase of an action potential?
Depolarization, where the membrane potential becomes less negative as Na+ channels open and Na+ enters the cell.
82
What occurs after the peak of an action potential?
Repolarization, as K+ channels open, allowing K+ to exit the cell and restoring the negative membrane potential.
83
What are graded potentials?
Changes in membrane potential that vary in magnitude and can lead to action potentials if the threshold is reached.
84
How do action potentials encode information?
Through the frequency and pattern of action potentials.
85
What is the resting membrane potential of a neuron?
Stable at -70 mV.
86
What happens to the membrane potential during stimulation?
It rapidly depolarizes and then repolarizes.
87
What determines the magnitude of graded potentials?
The number of ion channels that open.
88
What is the role of agonists in graded potentials?
Agonists bind to Na channels, enhancing depolarization.
89
What is the effect of antagonists on graded potentials?
Antagonists bind to K channels, reducing the likelihood of reaching threshold.
90
What is the process of summation in graded potentials?
The summation of electrical events occurs in space and time, affecting the overall membrane potential of the neuron.
91
What is the significance of ion channels in neuronal signaling?
Na channels lead to depolarization, while K channels lead to repolarization.
92
What happens when Na and K channels open simultaneously?
Their effects can negate each other, demonstrating the complexity of neuronal signaling.
93
What are ligand-gated ion channels?
Ion channels that respond to specific chemicals, leading to changes in membrane potential.
94
What are the steps of action potential generation?
1. Resting potential maintained with Na and K channels closed. 2. Agonist binding opens Na channels, causing gradual depolarization. 3. Voltage-gated Na channels open rapidly, leading to massive Na influx. 4. Na channels close, K channels open, allowing K to exit and repolarize. 5. Cell may become hyperpolarized before returning to resting potential.
95
How do action potentials propagate along the axon?
As a wave of depolarization, triggered by the previous segment's depolarization.
96
What triggers adjacent segments of the axon to generate their own action potentials?
The depolarization of one segment reaching threshold.
97
What are the main components of a neuron?
Neurons consist of dendrites, a cell body, an axon, and axon terminals.
98
What is the role of dendrites in a neuron?
Dendrites receive signals from other neurons.
99
What function does the cell body of a neuron serve?
The cell body integrates signals received from dendrites and decides on action.
100
What is the purpose of the axon in a neuron?
The axon transmits action potentials away from the cell body to the axon terminals.
101
What occurs at the axon terminals during synaptic transmission?
Action potentials trigger the release of neurotransmitters into the synapse.
102
How do neurotransmitters affect the target neuron?
Neurotransmitters bind to receptors on the target neuron's dendrites, influencing its membrane potential, which can either excite or inhibit the neuron.
103
What is the myelin sheath and its function?
The myelin sheath is an insulating layer around axons that increases the speed of signal transmission.
104
What is saltatory conduction?
Saltatory conduction is the process by which action potentials jump from one node of Ranvier to the next, speeding up signal transmission.
105
What are giant axons and their significance?
Giant axons, found in species like squids, allow for rapid responses and have been important for studying neuronal properties.
106
What is a synapse?
A synapse is the junction between two neurons where neurotransmitters are released to transmit signals.
107
What triggers neurotransmitter release at the synapse?
Neurotransmitter release is triggered by calcium influx, leading to vesicle fusion and release into the synaptic cleft.
108
How can cone snail toxin affect synaptic transmission?
Cone snail toxin can block calcium channels, interfering with neurotransmitter release.
109
What is the role of acetylcholine in the nervous system?
Acetylcholine is involved in muscle contraction and various brain functions.
110
What is the function of glutamate as a neurotransmitter?
Glutamate is an excitatory neurotransmitter that plays a role in learning and memory.
111
What are the effects of excessive glutamate?
Excessive amounts of glutamate can lead to excitotoxicity.
112
How do dopamine and serotonin influence mental health?
Dopamine and serotonin influence mood, reward, and various mental health conditions.
113
What is the post-synaptic response?
The post-synaptic response involves target cells modulating their sensitivity to neurotransmitters by adjusting receptor density and activity.
114
How is neurotransmission terminated?
Neurotransmission is terminated by reuptake into the presynaptic neuron or enzymatic degradation.
115
What are acetylcholinesterase inhibitors and their effects?
Acetylcholinesterase inhibitors prevent muscle relaxation by inhibiting the breakdown of acetylcholine.
116
How do pesticides like pyrethrum and DDT affect neuronal function?
Pesticides disrupt neuronal function by affecting sodium channels, leading to paralysis in insects.
117
What are neonicotinoids and their ecological impact?
Neonicotinoids are synthetic insecticides that mimic acetylcholine and contribute to bee population declines.
118
What are the human health risks associated with pesticides?
Many pesticides pose risks to human health, necessitating careful regulation and usage to prevent toxicity.
119
Why is understanding membrane potential important?
Understanding membrane potential is crucial for grasping how signals are generated and propagated in neurons.
120
Electrochemical Gradient
Combination of chemical and electrical gradients across membrane.
121
Exocytosis
Process of releasing neurotransmitters from storage vesicles.
122
Cytoplasm
Fluid inside the cell, relatively negative due to proteins.
123
Chemical Gradient
Concentration differences of ions across the membrane.
124
Electrical Gradient
Difference in charge across the cell membrane.
125
Resting Potential Direction
Reported as inside relative to the outside.
126
Depolarization
Decrease in membrane potential relative to resting state.
127
Hyperpolarization
Increase in membrane potential beyond resting state.
128
Repolarization
Return of membrane potential to resting state.
129
Sodium Gradient
Inward chemical gradient favors sodium entry.
130
Potassium Gradient
Outward chemical gradient favors potassium exit.
131
Equilibrium Potential
Voltage that balances chemical gradient for an ion.
132
Sodium Equilibrium Potential
Approximately +40 mV for sodium ions.
133
Potassium Equilibrium Potential
Approximately -90 mV for potassium ions.
134
Graded Depolarization
Variable change in membrane potential due to ion flow.
135
Agonist
Chemical that activates ion channels, increasing depolarization.
136
Antagonist
Chemical that inhibits ion channels, decreasing depolarization.
137
Threshold Membrane Potential
Voltage barrier triggering massive depolarization event.
138
Chemical Gradient
Concentration difference driving ion movement across membranes.
139
Electrical Gradient
Voltage difference influencing ion movement across membranes.
140
Voltage-sensitive Na channels
Channels that open during depolarization phase.
141
Depolarization
Inflow of Na ions increases membrane potential.
142
Resting state
Stable membrane potential before action potential.
143
Ligand-gated ion channels
Open in response to specific ligands.
144
Voltage-gated Na channels
Open in response to membrane voltage changes.
145
Tetrodotoxin
Toxin that blocks voltage-gated Na channels.
146
Equilibrium potential for K
Membrane potential where K ions are balanced.
147
Propagation of action potential
Wave of depolarization along the axon.
148
Axon hillock
Region where action potentials are initiated.
149
Ion gradients
Concentration differences of ions across the membrane.
150
K channels
Open to allow K ions to exit cell.
151
Na channels
Open to allow Na ions to enter cell.
152
Time and space summation
Combined effects of multiple signals over time.
153
Downstream depolarization
Subsequent areas of axon depolarize after initial.
154
Interneurons
Neurons connecting other neurons, processing information locally.
155
Motor Neurons
Neurons transmitting signals to muscle cells for movement.
156
Sensory Neurons
Neurons detecting stimuli from the environment.
157
Myelin
Insulating layer around axons speeding up signal transmission.
158
Saltatory Conduction
Jumping of action potentials between nodes of Ranvier.
159
Giant Axons
Large axons allowing for rapid action potential propagation.
160
Calcium Channels
Channels that open to trigger neurotransmitter release.
161
Cone Snail Toxin
Substance blocking calcium channels, inhibiting neurotransmitter release.
162
Analgesic Potency
Analgesic is 1000 times stronger than morphine.
163
Acetylcholine
Primary neurotransmitter for muscle contraction.
164
Glutamate
Potent neurotransmitter linked to excitability.
165
Dopamine
Neurotransmitter influencing mood and reward.
166
Serotonin
Regulates mood, sleep, and appetite.
167
Phosphorylation
Modification to enhance or reduce channel activity.
168
Acetylcholinesterase
Enzyme that degrades acetylcholine in synapse.
169
Blue Ringed Octopus Venom
Contains AChE inhibitor affecting muscle relaxation.
170
Snake Venoms
Mixture of toxins, some inhibit AChE.
171
Pyrethrum
Natural insecticide blocking sodium channels.
172
DDT
Pesticide affecting sodium channels, long-lasting effects.
173
Malathion
AChE inhibitor used as insecticide.
174
Neonicotinoids
Synthetic agonists mimicking acetylcholine.
175
Ligands
Molecules that bind to receptors triggering responses.
176
Neurotoxin
Substance disrupting normal nerve function.
177
What is the significance of cell signalling in multicellular organisms?
Cell signalling is crucial for the coordination of complex responses, distinguishing animals from other life forms.
178
Which organisms are highlighted as examples of effective cell signalling?
Cephalopods, showcasing rapid environmental responses through chemical pathways.
179
What is the central concept of cell signalling related to maintaining balance in the body?
Homeostasis.
180
What are the two main types of signalling factors based on solubility?
Hydrophilic (water-soluble) and hydrophobic (fat-soluble).
181
How do hydrophilic signalling factors behave in the body?
They dissolve in aqueous environments, can be stored in vesicles, and are released rapidly upon stimulation.
182
What is the release mechanism for hydrophobic signalling factors?
They are lipid-soluble, cannot be stored, and are released immediately upon synthesis.
183
How do hydrophilic and hydrophobic factors differ in their transport mechanisms?
Hydrophilic factors travel freely in extracellular fluid, while hydrophobic factors require carrier proteins for transport.
184
What role do hydrophilic factors play at target tissues?
They bind to membrane receptors, triggering intracellular signalling cascades.
185
How do hydrophobic factors influence gene expression?
They act as transcription factors, directly influencing gene expression.
186
Can you name some common hydrophilic signalling factors?
Insulin, glucagon, and prolactin.
187
What is a common characteristic of hydrophobic signalling factors?
They include steroids, which are synthesized from precursors and released immediately upon production.
188
What distinguishes hormones from other signalling factors?
Hormones specifically refer to factors that travel through the bloodstream, while 'factors' encompasses a broader range of chemical signals.
189
Give examples of local acting factors that are considered signalling factors but not hormones.
Acetylcholine and histamine.
190
What are the six key steps in the endocrine signalling pathway?
Synthesis, secretion, transport, binding, signal transduction, and response.
191
Where does hormone synthesis occur?
In endocrine glands based on genetic expression or biosynthetic pathways.
192
What happens to hormones after they are synthesized?
They are secreted into the bloodstream or extracellular fluid and become ligands that bind to receptors.
193
What occurs during signal transduction in endocrine signalling?
The receptor changes shape upon ligand binding, leading to downstream effects like enzyme activation or gene expression changes.
194
How is hormone synthesis controlled?
It is influenced by the chemical nature of the hormone; proteins are synthesized based on gene expression.
195
What is the storage and release mechanism for hydrophilic hormones?
They are stored in vesicles and released via exocytosis.
196
What is the importance of regulating hormone synthesis and secretion?
It is vital for maintaining homeostasis and responding to physiological changes.
197
How does the structure of prolactin vary across species?
Despite sharing a common lineage, prolactin varies in structure across different species.
198
What are the two classifications of hormones based on their structure?
Hormones are classified as either proteins or chemical products of biosynthetic pathways.
199
How are hydrophilic hormones secreted from cells?
Hydrophilic hormones are secreted via vesicles through exocytosis, requiring the endoplasmic reticulum (ER) and Golgi apparatus for intracellular sorting.
200
Where does the synthesis of hormones like epinephrine occur?
The synthesis of hormones like epinephrine occurs in the endoplasmic reticulum (ER).
201
What triggers the release of hormones into the bloodstream?
The release of hormones is triggered by signals that prompt vesicles to fuse with the cell membrane.
202
How do hydrophobic hormones circulate in the bloodstream?
Hydrophobic hormones require transport proteins, such as albumin and globulins, to circulate in the bloodstream.
203
What is the role of transport proteins for hydrophobic hormones?
Transport proteins protect hydrophobic hormones from degradation and help regulate their availability to target tissues.
204
What happens when a hormone binds to its receptor?
The binding of a hormone to its receptor induces a conformational change, affecting the receptor's function and interaction with other proteins.
205
Where can hormone receptors be located within a cell?
Hormone receptors can be located on the cell membrane or within the cell.
206
What is the significance of hormone-receptor specificity?
The specificity of hormone-receptor interactions is crucial; receptors are designed to bind only to their corresponding ligands.
207
How can cells adjust their sensitivity to hormones?
Cells can adjust their sensitivity by altering the number or type of receptors they express.
208
What are phytoestrogens and how do they affect hormonal signaling?
Phytoestrogens are plant-derived compounds that resemble estrogens and can interfere with hormonal signaling, particularly in vertebrates.
209
What are some examples of hormone receptors?
Examples include steroid hormone receptors (e.g., testosterone) and ion channel receptors (e.g., acetylcholine receptor).
210
How do G-Protein Coupled Receptors (GPCRs) function in hormonal signaling?
GPCRs interact with G-proteins, which transmit signals from the receptor to intracellular targets, amplifying the response.
211
What initiates a signaling cascade upon hormone binding?
Hormone binding initiates a signaling cascade often involving phosphorylation of relay molecules and activation of protein kinases.
212
What is the effect of activated kinases in signaling pathways?
Each activated kinase can phosphorylate multiple target proteins, leading to significant amplification of the signal.
213
What is the role of antagonistic hormones in homeostasis?
Antagonistic hormones, such as insulin and glucagon, have opposing effects on blood glucose levels.
214
What is the primary function of insulin in the body?
Insulin decreases blood glucose by promoting glucose uptake in muscle cells.
215
How does glucagon affect blood glucose levels?
Glucagon increases blood glucose by stimulating glucose production in the liver.
216
What is the relationship between insulin and glucagon?
Insulin and glucagon have opposing actions that regulate blood glucose levels, maintaining homeostasis.
217
What happens to insulin and glucagon levels after a meal?
After a meal, insulin levels rise to enhance glucose uptake, while glucagon levels drop.
218
Why is understanding insulin and glucagon important in the context of diabetes?
Diabetes is characterized by an imbalance of insulin, making the understanding of these hormones vital for management.
219
What are tropic hormones?
Tropic hormones regulate the secretion of other hormones and influence multiple endocrine glands.
220
Give two examples of tropic hormones.
Follicle Stimulating Hormone (FSH) and Adrenocorticotropic Hormone (ACTH).
221
What does the term 'tropic' indicate about these hormones?
It means 'to turn', indicating their role in directing hormonal activity.
222
What is the role of the hypothalamus in the endocrine system?
The hypothalamus integrates signals and regulates homeostasis through hormone release.
223
What are the two sections of the pituitary gland and their communication methods?
The anterior pituitary communicates via portal vessels, while the posterior pituitary releases hormones directly from hypothalamic axons.
224
What is the hypothalamus-pituitary (HP) axis?
It is crucial for controlling various physiological processes through hormone signaling.
225
What is the function of the adrenal medulla?
The adrenal medulla secretes epinephrine for immediate 'fight or flight' responses.
226
What does the adrenal cortex produce?
The adrenal cortex produces steroid hormones.
227
What is the HPA axis?
The Hypothalamic-Pituitary-Adrenal axis illustrates the interaction between the hypothalamus, pituitary, and adrenal glands during stress.
228
What hormones do FSH and LH stimulate in females?
FSH and LH promote estradiol production in females.
229
What hormones do FSH and LH stimulate in males?
FSH and LH stimulate testosterone production in males.
230
How do sex hormones affect primary and secondary sexual characteristics?
They lead to the development of primary and secondary sexual characteristics based on receptor types and signaling pathways.
231
What challenges exist in understanding endocrine pathways?
The complexity of hormonal signaling and the vast number of hormones and their interactions can make understanding challenging.
232
What should one focus on when studying hormonal signaling?
Focus on generalized concepts rather than memorizing every hormone, considering the plasticity of signaling pathways.
233
What are some recurring themes in hormonal signaling?
Signaling cascades, receptor interactions, and antagonistic hormone actions.
234
How do hormonal signaling differences manifest between sexes?
Differences in hormonal signaling can occur between sexes, populations, and species, highlighting evolutionary adaptations.
235
What is sensory biology?
The study of how organisms perceive their environment focusing on both traditional senses and diverse sensing mechanisms.
236
How does sensory perception vary among species?
It varies significantly as illustrated by unique adaptations like those of the star-nosed mole.
237
Why are sensory systems important for organisms?
They are crucial for interacting with the environment influencing behaviour and survival.
238
Give an example of how sensory systems regulate physiological responses.
The pancreas senses glucose levels to regulate metabolism.
239
What is the role of sensory information in energy balance?
It regulates energy balance through the interplay between the gastrointestinal tract, hypothalamus, and storage tissues.
240
What are neuronal receptors?
Specialized cells that detect stimuli and are also neurons allowing direct communication with the central nervous system (CNS).
241
How do neuronal receptors convey sensory information?
They utilize action potentials with the frequency of these potentials correlating with the intensity of the stimulus.
242
What are non-neuronal receptors?
Sensory cells that release signaling molecules to communicate with adjacent neurons.
243
What is an example of a non-neuronal receptor?
Hair cells which detect fluid movement and are crucial for hearing and balance.
244
How do hair cells function?
The bending of hair-like extensions (microvilli) alters membrane potential and neurotransmitter release.
245
What is the relationship between action potentials and signal transmission in hair cells?
Hair cells generate action potentials in response to fluid movement with frequency modulated by the bending of extensions.
246
What are pheromones?
Chemical signals released by exocrine glands that facilitate communication between individuals of the same species.
247
How do male silkworm moths detect female pheromones?
Their antennae are equipped with chemoreceptors that detect these pheromones.
248
What is chemosensing?
The detection of chemical stimuli through specialized receptors allowing effective interaction with the environment.
249
What are the primary forms of chemosensing?
Taste and smell.
250
What is a common myth about taste perception?
The myth of tongue mapping which suggests that specific zones on the tongue detect different tastes.
251
How do males use pheromones for mating?
They detect pheromones released by females allowing them to follow chemical trails.
252
What are pheromone traps used for in agriculture?
To monitor insect populations and control pest density effectively without harmful chemicals.
253
What is electrosensing?
The ability of certain animals to detect electrical fields generated by other organisms aiding in navigation and hunting.
254
How do electric fish utilize their electrical fields?
Electric fish generate and monitor their own electrical fields detecting disruptions caused by nearby objects.
255
What specialized sensors do hammerhead sharks and platypuses possess?
They possess specialized sensors to detect electric fields in their environment.
256
How do bees use static electricity while foraging?
Bees generate static electricity while flying, altering the electrical field of flowers to identify previously visited ones, optimizing foraging efficiency.
257
What is magnetosensing in animals?
Magnetosensing is the ability of many animals, including birds and turtles, to utilize the Earth's geomagnetic field for navigation during migration.
258
What aids migratory birds in navigation?
Migratory birds can detect changes in magnetic fields which helps them navigate long distances.
259
What role does C. elegans play in understanding magnetosensing?
C. elegans uses the geomagnetic field to determine vertical movement with dietary status influencing direction in artificial magnetic fields.
260
What part of the electromagnetic spectrum can animals primarily detect?
Animals can detect various wavelengths of electromagnetic radiation primarily within the visible spectrum.
261
How do different proteins in the eyes contribute to animal vision?
Different proteins absorb specific wavelengths allowing for color detection and response to light.
262
How do planaria navigate their environment?
Planaria utilize simple photodetectors to navigate based on light intensity.
263
What is the structure of insect eyes and how does it benefit them?
Insects possess compound eyes made up of ommatidia, providing superior visual acuity compared to humans.
264
How do dragonflies perceive motion differently than humans?
Dragonflies can see individual frames allowing them to detect rapid movements essential for hunting.
265
What is the flicker fusion frequency in dragonflies?
Dragonflies have a higher flicker fusion frequency enabling them to process visual information more rapidly than humans.
266
What are the two types of photoreceptor cells in the vertebrate eye?
The two types are rods, which are sensitive to low light levels, and cones, which are responsible for color vision.
267
What is the function of rods in the vertebrate eye?
Rods are sensitive to low light levels but do not distinguish colors utilizing rhodopsin for light detection.
268
What do cones in the vertebrate eye do?
Cones are responsible for color vision with three types corresponding to red green, and blue wavelengths.
269
What is bioluminescence?
Bioluminescence is the ability of certain organisms, like dragonflies, to produce light through biochemical reactions involving luciferin and ATP.
270
What is the significance of visual perception differences between humans and dragonflies?
The differences highlight evolutionary adaptations to environmental demands with dragonflies evolving for survival in dynamic habitats.
271
How do visual signals get processed in the vertebrate eye?
Visual signals are relayed by bipolar and amacrine cells to the optic nerve for interpretation by the brain.
272
What is the role of luciferin in bioluminescence?
Luciferin is involved in biochemical reactions that enable organisms to produce light.
273
What is the importance of light detection for animal behaviors?
The ability to detect light is crucial for behaviors such as navigation and foraging.
274
What case study demonstrates dragonflies' visual processing capabilities?
Research shows that dragonflies can track and intercept flying insects with remarkable accuracy.
275
What is the purpose of flashing patterns in fireflies?
Fireflies use specific flashing patterns for mating communication with females signaling males to attract them.
276
How have some species evolved in relation to firefly mating signals?
Some species have evolved to mimic firefly signals to lure and prey on males showcasing an evolutionary arms race.
277
What role does bioluminescence play for dragonfish in deep-sea environments?
Dragonfish utilize bioluminescence for communication and predation emitting light in the purple range while hiding their signals from predators.
278
What is a notable adaptation of dragonfish regarding their bioluminescent signals?
Dragonfish adapt by filtering their bioluminescent signals to red light which is invisible to most predators.
279
What is thermosensing and why is it important?
Thermosensing is the detection of temperature changes crucial for survival as it helps animals find prey and avoid danger.
280
How do pit vipers enhance their hunting capabilities?
Pit vipers have specialized organs that detect infrared radiation allowing them to hunt effectively in low-light conditions.
281
What are TRP channels and their role in thermosensing?
TRP channels are key proteins that respond to temperature changes linking thermal sensations to the nervous system.
282
What happens when TRP channels are activated?
Activation of TRP channels leads to depolarization and signal transmission enabling rapid responses to temperature variations.
283
How do chemical ligands interact with TRP channels?
The interaction of TRP channels with chemical ligands such as those in mint and chili, illustrates the complexity of sensory perception.
284
What is the function of mechanoreceptors in human skin?
Mechanoreceptors in human skin detect mechanical changes contributing to the sense of touch.
285
How are mechanoreceptors arranged in human skin?
Mechanoreceptors are arranged at various depths in the skin allowing for detection of different types of mechanical stimuli.
286
What is the significance of the connection between the extracellular matrix and cytoskeleton in mechanosensation?
This connection via transmembrane receptors is crucial for mechanosensation and the integration of sensory information.
287
What are statocysts and their function in animals?
Statocysts are specialized structures that detect orientation using ciliated receptor cells and a statolith allowing animals to sense gravity and maintain balance.
288
How does the statolith function in statocysts?
The statolith moves within the statocyst in response to changes in orientation activating sensory neurons to inform the animal of its orientation relative to gravity.
289
What is the lateral line system in fish?
The lateral line system consists of hair cells that detect water movement and pressure changes allowing fish to sense disturbances in their environment.
290
How does the brain process signals from the lateral line system?
The brain processes signals from the lateral line to interpret fluid movement and respond accordingly.
291
What is a case study related to the lateral line system in fish?
Research on how fish use the lateral line to avoid predators and locate prey in murky waters.
292
What are the key themes in sensory physiology?
Sensory physiology encompasses systems that detect and respond to stimuli relying on specialized receptors and neural pathways
293
Why is the integration of sensory information crucial for survival?
It influences behavior and interactions with the environment shaping animal behavior and adaptations.
294
What future research directions are suggested in sensory physiology?
Future research may focus on the molecular mechanisms underlying sensory perception and their applications in biotechnology.
295
What historical advancement revolutionized brain imaging and allowed visualization of individual neurons?
The introduction of green fluorescent protein (GFP) from jellyfish.
296
What does cephalization refer to in the context of nervous systems?
The concentration of sensory and neural structures at the anterior end of an organism enhancing its ability to process information.
297
What is the simplest nervous system represented by and what does it consist of?
The hydra which has a diffuse nerve net allowing basic movement and digestion.
298
What is neuronal plasticity and why is it important?
Neuronal plasticity is the adaptability of neural connections in response to experiences = crucial for learning and memory.
299
How do transcription factors relate to nervous system regeneration?
Transcription factors play a role in regeneration (as seen in planarians) providing insights for potential applications in human health.
300
What distinguishes cnidarians from more complex nervous systems?
Cnidarians (like hydras) possess a simple nerve net and lack true nervous systems but can respond to stimuli.
301
What capabilities do planarians exhibit that mark an early stage of cephalization?
Planarians have a more complex arrangement of neurons allowing for directional movement and sensory processing.
302
What advanced capabilities do cephalopods (such as squids) demonstrate?
Cephalopods have large brains capable of complex behaviors including problem-solving and camouflage.
303
What is the role of ganglia in cephalopods?
Ganglia indicate a decentralized nervous system allowing for localized processing of information.
304
What are the primary signaling cells in the nervous system?
Neurons.
305
What are the functions of glial cells in the nervous system?
Glial cells maintain homeostasis + provide insulation + protect against pathogens.
306
What is the function of myelin sheaths in the nervous system?
Myelin sheaths enhance signal transmission speed.
307
What forms the blood-brain barrier and its primary function?
The blood-brain barrier is formed by tightly connected endothelial cells -> preventing harmful substances from entering the brain.
308
How do astrocytes contribute to the blood-brain barrier?
Astrocytes regulate capillary permeability -> allowing the brain to respond to immune challenges while maintaining a stable environment.
309
What is the structural organization of the vertebrate brain?
The vertebrate brain is organized into grey matter (unmyelinated neurons) and white matter (myelinated axons).
310
What role does the spinal cord play in the nervous system?
The spinal cord serves as a conduit for signals between the brain and body and as a center for reflex actions.
311
What is the significance of reflexes in the context of nervous system complexity?
Reflexes allow for rapid responses to stimuli without conscious thought illustrating the adaptive significance of nervous system complexity.
312
What does the central nervous system (CNS) integrate and coordinate?
The CNS integrates sensory information and coordinates responses.
313
How does the hypothalamus differ in terms of blood-brain barrier permeability?
The hypothalamus has a less restrictive barrier -> enabling it to monitor blood composition and regulate homeostasis.
314
What evolutionary patterns are explored in the lecture regarding nervous systems?
The evolutionary patterns of complexity and cephalization across species.
315
What is the relationship between neuronal plasticity and learning?
Neuronal plasticity allows for the adaptation of neural connections which is essential for learning and memory.
316
What insights can be gained from studying planarians in relation to nervous systems?
Planarians' ability to regenerate lost body parts serves as a model for studying cellular growth and repair mechanisms.
317
What evolutionary trend is reflected in the development of nervous systems?
The evolution of nervous systems reflects a trend towards increased complexity and specialization in response to environmental challenges.
318
What are the two main divisions of the nervous system?
The central nervous system (CNS) and the peripheral nervous system (PNS).
319
What does the central nervous system consist of?
The brain and spinal cord.
320
What is the role of neurons in the nervous system?
Neurons are the fundamental units that transmit signals through axons to communicate with other neurons.
321
What is the primary function of the peripheral nervous system?
To relay sensory information to the CNS and execute motor commands from the CNS.
322
What is a reflex action?
An automatic response to stimuli that demonstrates the efficiency of the nervous system.
323
Describe the knee-jerk reflex. What triggers it?
The knee-jerk reflex occurs when a doctor taps the knee _> triggering a sensory neuron to send a signal to the spinal cord -> activating a motor neuron to contract the quadriceps muscle.
324
What components are involved in a reflex arc?
Sensory neurons + interneurons + motor neurons.
325
How can reflexes be modified?
Reflexes can be modified by higher brain functions such as when cold stimuli cause erratic muscle contractions instead of coordinated movements.
326
What is the motor system responsible for?
Controlling skeletal muscles through motor neurons.
327
What are the two types of motor neurons?
Upper motor neurons (originating in the brain) and lower motor neurons (located in the spinal cord).
328
What condition can result from disorders affecting motor neurons?
Amyotrophic lateral sclerosis (ALS) which impacts muscle control and movement.
329
What does the autonomic nervous system regulate?
Bodily functions such as heart rate and glandular activity.
330
What are the three main components of the autonomic nervous system?
The sympathetic + parasympathetic + enteric systems.
331
What is the function of the sympathetic division of the autonomic nervous system?
To prepare the body for 'fight or flight' responses + increasing heart rate + energy mobilization.
332
What does the parasympathetic division promote?
'Rest and digest' activities + slowing heart rate + enhancing digestion.
333
What is the role of the enteric nervous system?
To control gastrointestinal functions independently + coordinating muscle contractions and secretions.
334
What are the three main regions of the vertebrate brain?
Forebrain + midbrain + and hindbrain.
335
What is the primary function of the forebrain?
Involved in sensory processing and higher cognitive functions.
336
What does the midbrain do?
Acts as a relay center -> integrating sensory information and coordinating motor responses.
337
What basic functions does the hindbrain control?
Basic life functions including movement and balance.
338
How do brain structures vary among vertebrates?
Variations are based on ecological needs and behaviors with simpler structures in some species and larger motor regions in more complex vertebrates.
339
What role does the hypothalamus play in the CNS?
Maintains homeostasis by regulating various bodily functions.
340
What is neural plasticity?
The brain's ability to adapt and reorganize itself in response to experiences.
341
What was the case study of Henry Molaison (HM) significant for?
It demonstrated the effects of hippocampus removal resulting in an inability to form new short-term memories while retaining long-term memories.
342
What traumatic brain injury case study provided insights into the role of the frontal lobe in emotional regulation?
Phineas Gage.
343
What does the Peripheral Nervous System (PNS) connect?
The PNS connects the Central Nervous System (CNS) to the limbs and organs.
344
What are the two main pathways of the Peripheral Nervous System?
Afferent (sensory) pathways and efferent (motor) pathways.
345
What is the function of afferent nerves in the PNS?
Afferent nerves carry signals to the CNS.
346
What is the role of efferent nerves in the PNS?
Efferent nerves send commands from the CNS to the body.
347
What does the autonomic nervous system regulate?
Involuntary bodily functions.
348
What are the two divisions of the autonomic nervous system?
Sympathetic and parasympathetic divisions.
349
What is the primary function of the sympathetic division of the autonomic nervous system?
It prepares the body for 'fight or flight' responses.
350
What does the parasympathetic division promote?
'Rest and digest' activities + conserving energy and facilitating bodily maintenance.
351
What are Central Pattern Generators (CPGs)?
Neural networks that generate rhythmic patterns of motor activity.
352
How do CPGs operate in relation to sensory feedback?
They can operate independently of sensory feedback although sensory inputs can modulate their activity.
353
What activities are CPGs involved in?
Walking + breathing + swimming.
354
What insights can studying CPGs provide?
Insights into rehabilitation strategies for movement disorders.
355
What model organisms have been used to study CPG function?
Lobsters and Aplysia.
356
What specific neurons in lobsters control leg movements?
LP + PY + PD neurons.
357
What is neural plasticity?
The brain's ability to reorganize itself by forming new neural connections throughout life.
358
Why is neural plasticity important?
It is essential for learning + memory + recovery from brain injuries.
359
What does the phrase 'use it or lose it' refer to in the context of neural plasticity?
The importance of regular neural activity in maintaining synaptic strength.
360
What is Long-Term Potentiation (LTP)?
A long-lasting enhancement in signal transmission between two neurons resulting from repeated stimulation.
361
What role do NMDA and AMPA receptors play in LTP?
They are critical for synaptic strengthening during the process of LTP.
362
What triggers the intracellular signaling pathways in LTP?
Calcium influx through NMDA receptors.
363
How does LTP contribute to learning and memory?
It provides a molecular basis for how experiences shape neural circuits.
364
What is the complexity of the nervous system described as?
A highly complex network that evolved to control a wide range of functions.
365
What does understanding the subdivisions of the nervous system help with?
It helps in grasping how different systems interact to maintain homeostasis and respond to stimuli.
366
What does it mean that brain size is relative?
Comparing total brain size among species doesn't provide insight into cognitive abilities; instead, comparing brain size relative to body size is more informative.
367
How can brain size relative to body size indicate cognitive abilities?
Species with larger brains than expected for their body size may have superior cognitive abilities compared to those with smaller brains than expected.
368
What does a larger brain region indicate about its importance?
A brain region that is larger than expected for total brain size likely plays a more significant role in the species' ecology.
369
Why is the brain considered expensive in terms of energy?
The brain requires a lot of glucose and oxygen, making its energetic needs higher than many other tissues.
370
What is the relationship between larger neural tissues and processing power?
Larger brain tissues contain more neurons, which allows for greater information processing capabilities.
371
What trade-offs are involved in brain evolution?
Increasing brain size can save energy but may lead to a loss of functionality, highlighting the trade-offs between energy costs and processing power.
372
What does the principle of proper mass suggest?
The amount of neural tissue mass is proportional to the complexity of the functions that neural region must process.
373
What is the cognitive buffer hypothesis?
This hypothesis suggests that larger brains and advanced cognitive abilities are advantageous in challenging and changing environments.
374
What significant finding did Allen discover about the bamboo bat's brain?
The bamboo bat has the smallest relative and absolute brain size among bats, with essential brain regions preserved while those for higher cognitive functions are reduced.
375
What did Allen's comparative study of Leaf Nosed Bats reveal about olfactory bulb size?
Bats that eat fruit have larger olfactory bulbs than blood-eating bats, with insectivorous bats having intermediate sizes, supporting the principle of proper mass.
376
What findings did Allen report regarding urban tolerance in birds?
Bird species that thrive in urban environments have larger optic lobes and smaller hyperpalliums compared to those that avoid cities.
377
What question is Allen investigating regarding urban-tolerant birds?
Whether urban-tolerant birds have always had an 'urban brain' or if they have evolved in response to urbanization.
378
What is the significance of the optic lobe in urban birds?
A larger optic lobe in urban birds may indicate adaptations for navigating and surviving in city environments.
379
How does the size of the olfactory bulb relate to dietary habits in bats?
Frugivorous bats need to detect and differentiate more odors, leading to larger olfactory bulbs compared to insectivorous and hematophagous bats.
380
What does a smaller hyperpallium in urban birds suggest?
It may indicate a shift in cognitive processing needs in response to urban environments.
381
What is the role of glucose and oxygen in brain function?
They are critical for supporting the high energetic demands of brain activity.
382
How does brain evolution reflect trade-offs in energy and functionality?
Increasing brain size can enhance processing power but may also incur higher energy costs, necessitating a balance.
383
What is the relationship between brain region size and ecological importance?
Larger brain regions are likely more crucial to the species' ecological functions and adaptations.
384
What does the term 'cognitive buffer' imply in the context of brain evolution?
It implies that advanced cognitive abilities can help species cope with environmental challenges.
385
How can the study of museum specimens contribute to understanding urban bird brains?
It can help determine if urban-tolerant birds were pre-adapted to city life or if they evolved new traits in response to urbanization.
386
What does the preservation of essential brain functions in the bamboo bat suggest?
It indicates that basic survival functions are prioritized over higher cognitive capabilities in the evolution of smaller brains.
387
what is organismal physiology
the study of how organisms function in different environments and change within their lifetime (through plasticity)
AKA how organisms function within their external environment
388
what is a physiological system
a collection of processes/components of living organisms that interact and share a common purpose/perform a shared function
389
what are 7 essential functions of living organisms?
1. Supply cells with oxygen, glucose and nutrients to grow and make energy
2. remove waste products (CO2, NH3, H2o, etc)
3. maintain conditions required for proper molecular, cellular, and tissue function in homeostasis
4. sense and respond to changes in the internal and external environment
5. communicate/coordinate with other cells, tissues, etc
6. protect body from internal/external threats
7. reproduce
390
what are abiotic factors
non-living components of ecosystem like water soil, atmosphere
391
what are biotic factors
living things
392
what is a proximate hypothesis
a mechanistic cause (ie how does it work) and development (how did it develop) based on immediate questions
393
ultimate hypothesis
functional (why does it do it/what purpose) and evolutionary (why did it evelove)
394
null hypothesis
initial assumptuon of no relationship between variables + controlling one variable has no effect on others
+ the baseline for experiments by trying to prove null hypothesis wrong (p>0.005)
395
mutually exclusive
when hypothesis contradict each other and can't happen simultaneously
396
Scientific Process Steps
Observations -> questions -> hypothesis-> predictions -> studies
397
Observations in scientific processes
descriptions of nature and interesting patterns/phenomena
398
questions in scientific process
formalized research questions based directly on observations
399
hypothesis in scientific process
all plausible direct answers to question
*** must be rejectable
400
predictions in scientific process
quantifiable, definitive assertions that are direct from hypothesis
= diagnostic = tangible evidence you can collect if hypothesis is true
