Flashcards in unit 8 Test Study Deck (14):
Contrast signaling by hormones and signaling by neurons
Neuron transmit signals through nerve impulses, between specific locations in the body. In each system, the type of pathway used is the same
When signaling by hormones, different hormones cause different effects and only cells that have receptors will respond. Depending on the receptor the hormone may affect one area or many area.
Hormones are slow acting and are long lasting while neurons travels fast.
The nervous system conveys information by the pathway signals take.
Hormones are for changes that affect the whole body.
Neurons are for directing immediate response.
Contrast endothermic and ectothermic animals including behaviors
Endothermic- mainly birds and mammals, warmed most of the time by heat generated by metabolism. Function well in different environments. Animals like this are still active during the winter.
Ectothermic- mainly amphibians, gain most of the energy from the external sources. Tend to be inactive during the winter and warm up in the sun. Consumes less food
Explain how size and activity influence metabolic rate
Because larger animals have more body mass therefore it needs more chemical energy. Metabolic rate remains proportional to body mass to the three-quarter power
the energy it takes to maintain each gram of body mass is inversely related to body size.
The smaller animals higher metabolic rate per gram demands a higher rate of oxygen delivery and therefore have a breathing rate and heart rate, and must eat more food per unit of body mass.
Activities could affect the metabolic rate because activities would requires more energy and therefore cause more energy to produce.
Name four types of phagocytic leukocytes.
Natural killer cells
Describe the inflammatory response
inflammatory response the changes brought by the signaling molecules due to injury or infection.
Histamines are release at the site of the damaged, Macrophages secrete cytokines, and signaling molecules cause nearby capillaries to dilate.
Capillaries widen and become more permeable, allowing fluid containing antimicrobial to enter the tissue. Signals released by immune cells attract neutrophils
Neutrophils digest pathogens and cell debris at the site, and the tissue heals.
Explain why the antigen receptors of lymphocytes are tested for self-reactivity during development. Predict the consequences that would occur if such testing did not take place
Because they are randomly rearranged and if they are not inactivated the body could not distinguished between it and its own cells. If it is not being tested our body would attack our own cells as well.
Outline the steps of clonal selection
Antigen bind to the antigen receptor of only one of the three B cells.
Selected B cell proliferates, forming a clone of identical cells bearing receptors for the antigen.
Some daughter cells developed into long-lived memory cells that can respond rapidly to the same antigen.
Other daughter cells developed into short-lived plasma cells that secrete antibodies specific for the antigen.
Describe the structure of neurons and how their structure relates to their function
- most organelle including nucleus located in the cell body
- have highly branded extensions called dendrites, it receives signals from other neurons
- axon transmits signals to other cells ( longer than dendrites), divides into many branches
- axon hillock- cone-shaped base of an axon, where signals that travel down the axon are generated.
- synapse - where each end branch of axon transmit information to another cell
- neuron transmitter transmit the informations
- neurons with highly branched dendrites can receive input through large amount of synapses. Highly branch axons can transmit information to many targeted cells.
Describe the function of astrocytes, radial glia, oligodendrocytes, and Schwann cell’s.
-oligodendrocytes- forms insulating myelin sheaths around the axons of neurons in the central nervous system
- Schwann cells- wrap themselves around axons, forming layers of myelin
- radial glia- form tracks along which newly formed neurons migrate from the neuron tube.
- astrocytes- regulates the flow of blood.
Outline the role of voltage- gated ion channels in action potential
-When the membrane of the axon is at the resting potential, most voltage-gated sodium channels are closed. Some potassium channels are open, but most voltage- gated potassium channels are closed.
- A stimulus opens some sodium channels. Na inflow through those channels depolarizes the membrane. If the depolarization reaches the threshold, it triggers an action potential
- Depolarization opens most sodium channels, while the potassium channels remain closed, Nat influx makes the inside of the membrane positive with respect to the outside
- most sodium channels become inactivated, blocking Na inflow. Most potassium channels open, permitting K+ outflow, which makes the inside of the cell negative again.
- The sodium channels channels close, but some potassium channels are still open. As these potassium channels close and the sodium channel become unblocked, the membrane returns to its resting state
Describe saltatory conduction
mechanism for action potential propagation.
In a myelinated axon, the depolarizing current during the action potential spreads along the interior of the axon to the next node, the sodium channels allows reinitiation and the action potential jumps from one node to another as it travels along the axon.
List, give an example, and describe the example for the five classes of neurotransmitters
Acetylcholine is vital for nervous system functions that include muscle stimulation, memory formation, and learning. One example will be ligand-gated ion channel, the site where motor neurons synapse with the muscle cell.
Amino Acids- active in CNS and PNS. One example would be glutamate. Synapses where glutamate is the neurotransmitter have a key role in the formation of long term memory.
Biogenic Amines- example would be norepinephrine, which is made from tyrosine and it is an excitatory neurotransmitter in the autonomic nervous system.
Neuropeptides- example would be endorphin, which functions as natural analgesic, decreasing the pain perception.
Gases- example would be nitric oxide, which acts as a local regulator.
Contrast the cerebrum, cerebellum, diencephalon, and brainstem by including the location and function of each
Cerebrum- controls skeletal muscle contraction and is the center for learning, emotion, memory, and perception. Divided into left and right cerebral hemisphere. It is the upper-most part of our brain.
Cerebellum- coordinates movement and balance. It also help to learn and remember motor skills. It receives sensory information includes the hearing and visual system. It monitors motor commands issued by the cerebrum. Located below the cerebrum.
Diencephalon- includes thalamus, hypothalamus, and epithalamus. Thalamus is the main input center for sensory information going to the cerebrum. Hypothalamus contains the body’s thermostat and the biological clock. Epithalamus includes the pineal gland. Located in the cerebrum.
Brainstem- includes pons, medulla, and oblongata. It receives and integrate sensory informations and sends to locations in the forebrain and also coordinates visual reflexes. The pons and medulla help to transfer information between the midbrain and the forebrain. It is attached to the cerebellum.