Physiology
Nevian
Nevian
Fichier Détails
| Cartes-fiches | 160 |
|---|---|
| Langue | English |
| Catégorie | Biologie |
| Niveau | Université |
| Crée / Actualisé | 19.01.2017 / 25.01.2017 |
| Lien de web |
https://card2brain.ch/box/20170119_physiology
|
| Intégrer |
<iframe src="https://card2brain.ch/box/20170119_physiology/embed" width="780" height="150" scrolling="no" frameborder="0"></iframe>
|
structure skeletal muscle
Skeletal muscle is made of bundels of muscle fibers wich are composed of myofibrils. Functional unit: Sarcomer
Sarcomere:
H-Zone (Myosin)
I-Bande (Aktin-Filamente) 0.8 μm
A-Bande I-Bande (Aktin-Filamente) 0.8 μm (Myosin-Filamente. u. Aktin+Myosin Filamente überlagert) 1.5 μm
M-Linie (Myosin über Strukturproteine (z. B. Myomesin) verankert Creatinkinase assoziiert)
Contraction: The Cross-Bridge Cycle
Muscle: Membrane Systems of Skeletal Muscle
Excitation-Contraction Coupling (ECC) in Skeletal Muscle
Time Course of electrical ➜ mechanical Phenomena
All-or-none response of a single twitch of a muscle fiber
Recruitment of motor units Principle:
Recruitment of motor units Principle:
superposition of the single twitches of muscle fibers of several motor units ➜ spatial summation
How is muscle force regulated
Single twitches
Superposition of 2 single twitches
Tetanus
Muscle spindle - Sensory Receptors
different fiber types
Smooth Muscle Cells: general properties
Smooth Muscle: types (Multi-Unit, Single-Unit)
Smooth Muscle: Electrical Activity, Myogenic Tone
ECC Mechanism in Smooth Muscle
The motor system generates 3 classes of movements:
1. Reflex movements
2. Rhythmic movements
3. Voluntary movements
The Motor Unit
Spinal Reflexes
- Proprioreceptive reflexes:
- Extraneous reflexes:
Muscle Spindle
γ-Innervation
The γ-Innervation controls the sensitivity of the muscle spindle and maintains that sensitivity during a contraction
The Tendon Reflexes
- monosynaptic reflex
- Proprioreceptive reflexes
Flexor Reflex
- Extraneous reflexes
- polysynaptic reflex
The Motoneuron as Final Common Path
The activity of cortical pyramidal cells
Areas of conscious movement planning
Cerebellum and and basal ganglia loops support the cortex in motor planning
Biochemical basis of Hebbian learning
Hebb‘sche Regel (`fire together wire together ́)
classification of memory
Declarative memory: events + facts
episodic personal events (Where was I?)
remembering via contex Hippocampus-dependent
semantic facts, symbols (When? March 2011)
facts episodic memory is semantised, i.e. context of learning is not necessary anymore for remembering (days weeks).
=> becomes Hippocampus-independent, settles in neucortex
Implicit memory: classical conditioning
hippocampus, neocortex
Im Hippocampus fließen Informationen verschiedener sensorischer Systeme zusammen, die verarbeitet und von dort zum Cortex zurückgesandt werden. Damit ist er enorm wichtig für die Gedächtniskonsolidierung, also die Überführung von Gedächtnisinhalten aus dem Kurzzeit- in das Langzeitgedächtnis.
Unter Neocortex wird der multisensorische und motorische Teil der Großhirnrinde von Säugetieren verstanden. In Abgrenzung dazu existieren die Begriffe Archicortex (u. a. Hippocampus) und Paläocortex (u. a. Riechkolben).
Moleculare basis of (long-term) memory
Simultaneuos pre- and postsynaptic activity, e.g. presyn. spike 10ms before postsyn. spike à Ca 2+ - entry through NMDA receptor (that is activated with postsyn. depolarization and glutamate) à LTP
Unilateral activation, pre- or postsynaptic only, or first post then 10ms later presyn. spike à no NMDA activation, only little Ca 2+ -entry à LTD
The Eye
Presbyopia
Structure of the retina
Humans, Old-World monkeysà Trichromates (blue, green, res).
Receptive fields are created by combining photoreceptors
Human range of hearing
Comparing hearing precision:
Comparing hearing precision:
- vertical direction: ~20° by auricle: 10 dB SPL
- horizontal direction: ~2°
The middle ear acts as a mechanical amplifier
1.3*17=22
Hair cells
Inner hair cells: Afferents
Outer hair cells: Efferents
