16April - Muscles Flashcards
Protosomes
Ventral Nerve Cord
Include acoelomates, platyzoa, lophotrochozoa
Deurterostomes
Dorsal nerve cord Xenoturbellida Echinodermata hemichordata Urochordata Cephalochordata Vertebrata
Waggle Dance
Honey bees use waggle dance to send others to get food
Vibrational Cue
Wolf and salticid spiders
Used in mating
Steps of Response
- Receptors sense stimuli
- Sensory neurons transmit pinch message
- Message is interpreted
- Response is sent to motor neurons
- Muscles are activated and you pull away
Path of response signal
Touch
Nerves sense stimuli
Dendrites carry this down axon of sensory neurons
The process repeats in interneuron
Signal travels down ganglion
Ends at axon terminals of motor neurons
Movement
Requires ATP
Can be aerobic - requires O2
Anaerobic - requires lactate dehydrogenase
More efficient O2 transport = faster response to the environment
Ficks Law
Diffusion ions move from high to low concentrations To maximize diffusion: -Increase concentration gradient -Increase permeability of the membrane -Increase charge gradient
Electrical and chemical gradients can be used in conjunction to adjust flow rate
Inside of a cell is negative
Outside of a cell is positive
Resting membrane Potential (RMP)
electrical gradient between a resting neuron and environment
Membranes and pumps keep ions from flowing with gradient so RMP is nonzero
RMP of NaK pump: -70mV
Nerve Impulse Transmission
Outside of the cell is negative because:
- Na/K pump: 2K+ infor every 3 Na+ out
- Ion leakage channels: Let more K out than Na in
Synapses
Presynaptic: transmitting signal
Synapse: gap that signal crosses
Post-synaptic: receive signal (neurons, muscles, endocrine glands)
Ca and Neurotransmitters
- Action potential arrives at axon terminal
- Voltage gated Ca2+ channels open
- Ca2+ enters cell
- Ca signals to vesicles
- Vesicles move to membrane
- Docked vesicles release neurotransmitters
- Neurotransmitters diffuse across synaptic cleft and bind to receptors
The diffusion distance is short to allow this to happen rapidly
To increase the rate of diffusion:
- increase conc of neurotransmitter
- increase surface are of postsynaptic cell
- decrease distance between pre and post synaptic cells
What 3 ions are needed to cause a response?
Na+
K+
Ca++
Skeletal Muscle Contraction
Sliding filament mechanism
Myofibrils contract
Myofilaments slide relative to each other
1.Tropomyosin: covers binding sites on actin
2. Troponin opens binding sites when enough Ca++ builds up
3. Myosin head binds to actin
4. Myosin pulls on actin filaments
5. ATP releases myosin head
6. ATP cleaves into ADP
7. ADP cocks myosin head to prepare for next stroke
Skeletal Muscle
Actin: thin, twisted filaments Myosin: thick filaments with hooks Voluntary Fast response Moves the body - attaches to skeleton
Other types of muscle
Smooth: auto, slow response, skin, respiratory, etc
Cardiac: auto, fast response, heart
Types of skeletons
A. Hydro static - Worms, jellyfish
B. Exoskeleton - Insects
C. Endoskeleton - Vertebrates
Hydrostatic Skeleton
Worms, jellyfish Longitudinal and circular muscles Fluid filled cavity Flexible Easily crushed
Exoskeletons
Surrounds the body Arthropods Made of chitin Protects internal organs Strong but flexable at joints Limits body size Sometimes has to be shed to grow
Endoskeletons
Bones inside Attach to muscles Bones and cartilage and can grow and change unlike chitin Bones store nutrients Continuous growth
Phylum Annelida
Segmentation Closed circulatory system Neural connections between segments Hydrostatic skeleton Worms
Phylum Arthropoda
Jointed appendages Chitinous exoskeleton Fusion of body segments Open circulatory system Respiratory system different from circulatory Ventral nerve cord Excretory systems most insects
Phylum Echinoderms
Deuterostomes form anus first? Bilateral embryo Penamerous radial adults Water vascular system Move via hollow tube feet inflated by ampulla Starfish
Phylum Chordata
deuterostome coelomates
fishes, amphibians, reptiles, birds, mammals
Somites: segmented blocks of muscles
