BT EXAM II Flashcards
(33 cards)
What is the archetype skeletal structure?
An animal that is segmented from head to tail (Goethe: The skull is segmented like the spine is)
What are the 3 components of the skull?
Plates, Blocks, Rods
Dermatocranium: Membraneous bones; plate-like and form skull roof + palate
Chondrocranium: Cartilaginous bone forming most of the braincase
Viscerocranium: Structures that are derivative of the pharyngeal/gill arches.
What cartilage in the head does the 1st and 2nd P arches correlate to?
1st: lower jaw, middle ear
2: Jaw joint/gill apparatus, hyoid apparatus, cricoid, middle ear
Ventral Nerve Cord
pseudo-spinal cord in invertebrates
Dorsal Nerve Cord
Vertebrates - Above notochord, makes Brain + Spinal Cord. Essential for CNS.
Transmits sensory info to the brain, and motor info from brain to body
What are Tunicates?
A type of chordate who’s larvae have key CNS features. Supports Common Ancestry
What is the Garstang hypothesis?
The hypothesis that vertebrates evolved tunicate-like chordates. Via Paedomorphosis, retaining CNS features into adulthood
What are the organizations in the vertebrate nervous system (NS)?
- Sympathetic NS
- Parasympathetic NS
- Cranial Nerves
- Autonomic Nerves
How do the brain and spinal cord develop?
The ends of the neural plate of the ectoderm above the notochord start to converge, forming the neural tube. The leftover ectoderm forms the epidermis.
The brain starts forming at the cranial end of the tube, with swellings that begin to fold over themselves. Fore-, Mid-, and hindbrain
The spinal cord begins to develop on the other side of the tube.
What is the structure of a neuron
Dendrites: Receive signal from other neurons + environment
Soma: Nucleus of the neuron. Genetic info, maintains structure, provides energy
Axon: Transmits action potentials to other cells
Synapses: Specialized cell-cell contact site. Facilitates transmission of info between neurons
Myelin sheath: Sheath of fats and protein that protects part of neurons. We are unmyelinated at birth, and babies needs diets high in fat. Synapomorphy of jawed vertebrates
What types of neurons are there?
Motor: Typical structure; connect to muscles, glands, and organs. Inward->Outward
Sensory: Reacts to environmental input, physical or chemical. Axon in Center. Outward -> Inward
Interneuron: In-between and connecting motor + sensory neurons in the spine. communicate with each other. typical body plan. No myelin sheath
What is an astrocyte?
A molecule that connects blood vessels to neurons
What is a somatic nerve
Nerves in CNS responsible for voluntary movement
What is a Visceral nerve?
Nerves in CNS for involuntary movement of guts/viscera
What is a spinal nerve?
Composed of Dorsal + Ventral roots merging outside spinal cord
What is the sensory loop in the PSNS?
Dorsal root carries info from the body to the spine/CNS
Ventral root carries info from brain/CNS to body. Spinal Cord -> Ventral -> muscle
What is the autonomic NS?
Controls involuntary functions like breathing, heartrate, digestion
Sympathetic nervous system
Flight or fight; incerases heart rate, blood pressure, respiratory rate, dilates pupils.
Decreases digestion + urine production
Short preganglionic fibers, lost postganglionic fibers
Parasympathetic nervous system
Rest and Digest; increases digestion
decreases: art rate, blood pressure, respiratory rate, pupil dilation
Long preganglionic fibers, short postganglionic fibers
What is an example of autonomic and voluntary nerves working together?
Controlling the bladder. External sphincter voluntary, internal one not. Stretch response prompts PSNS response.
Cranial Nerves
Essential for processing sensory information + carrying out motor functions
I
Olfactory Nerve - sensory
II
Optic nerve - Retina - Sensory
III
Oculomotor- Motor
