BIOL 3350 EXAM 2

Thermoneutral zone

Range of temperatures where a being can maintain normal body temperature without excessive energy use.

Basal metabolic rate

Minimum number of calories body needs to function at a basic level.

Metabolic scaling

A phenomenon that describes how metabolic rate relates to body size, measured by oxygen rate.

Allometric scaling

A type of scaling where one trait increases more rapidly than another, often based on species size.

Isometric scaling

A type of scaling where everything increases proportionally relative to body size.

Essential amino acids

Amino acids that cannot be synthesized fast enough for demand and must be obtained through diet.

Essential fatty acids/lipids

Fatty acids required for energy storage, cell functions, and absorption of vitamins.

Small intestine aka - midugt

The part of the digestive system where main digestion and absorption of proteins, carbohydrates, and lipids occurs.

Large intestine aka - hindgut

Absorbs water and stores waste in the digestive system.

Pancreas

An organ that secretes enzymes into the small intestine to break down proteins.

Endopeptidases

Enzymes that require activation as they break down proteins and need to avoid self-digestion.

Digestion

The breakdown of food by endogenously produced enzymes.

Fermentation

The breakdown of food by enzymes produced by microbial symbionts.

Neuroplasticity

The ability of the brain to change its structure and function based on experiences.

Depolarization

A state where the inside of the cell is negative, typically associated with excitatory signals.

• voltage gated ion channels open and allow sodium ions to flow into the cell, making the inside more positive.

Hyperpolarization

A state where the inside of the cell becomes positive.

Exocytosis

The process of releasing large molecules from the cytoplasm to the cell exterior.

Endocytosis

The internalization of proteins, polysaccharides, and other cells, important for cell signaling.

Action potential

A rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane.

Oligodendrocytes

Glial cells responsible for myelin sheath production in the central nervous system.

Schwann cells

Glial cells that produce myelin sheath in the peripheral nervous system.

Astrocytes

Star-shaped glial cells that connect neurons to blood vessels and aid in neurotransmitter uptake.

Microglial cells

Glial cells that mediate immune responses and consume pathogens through phagocytosis.

Rod cells

Photoreceptor cells in the eye that respond to dim light.

Cone cells

Photoreceptor cells in the eye that respond to bright light.

Cerebrum

Part of the brain responsible for higher sensory and motor functions, learning, memory, and emotions.

Hypothalamus

Region of the brain responsible for homeostatic and endocrine regulation.

Cerebellum

Region of the brain involved in motor coordination.

Medulla oblongata

Part of the brain that controls autonomic and respiratory functions.

Olfactory bulb

Brain structure that receives neural input about smells from the nasal cavity olfactory epithelium.

• dendrites extend to mucous layer and ends to dendritic knob to the sensory cilia

• axons connect to olfactory bulb in forebrain

Elephant, bear, wolf, raccoon, mouse

Arrange animals from lowest mass-specific metabolic rate to highest: elephant, raccoon, wolf, bear, mouse

bile salt

____ aids in the digestion of lipids by emulsifying

lipids

Energy reserves in the body are stored mainly as:

what are immune cells?

microglia

increase speed of action potential

what is the function of myelin sheaths on the axon?

the peripheral nervous system is made of the:

• brain

• spinal cord

none of the above

What facilitates the slowest form of communication at a synapse?

metabotropic receptors

Small-molecule neurotransmitters are synthesized in the ___ while neuropeptides are synthesized in the ___.

axon terminals, cell body

autonomic nervous system

The pancreas is controlled by the

Skeletal muscle movement is controlled by the:

somatic nervous system

sympathetic nervous system

Which uses norepinephrine as a neurotransmitter?

why do animals need nitrogen

they are essential building blocks of amino acids, which are required for most bodily functions

how does the body absorb lipids?

brokedown by lipidase → fatty acids emulsified by bile salts into small droplets → carried to cell membranes by micelle

Vitamins

compounds that can’t be synthesized, must be consumed by plants

once consumed vitamins are released, and we adapt to needing them

lipid soluble in vertebrates, water soluble for general functions

responsible for breaking down ingested food with bacteria in the gut microbe

what is beneficial about symbiotic microbes in digestion?

ruminants

consume plant material with regurgitation to imporve digestibility

hindgut fermenters

use microbes in the cecum/colon for further digestion

what can cause gut microbiome across species?

varies due to genetics, diet, and environmental factors

4 factors of a neruon:

• dendrite

• soma

• axons

• presynaptic

dendrite

recieves input from other neurons

soma

integrates input signals, filled with cargo packaged to be carried and released at other end of the neurons

axons

carries signals from cell body to synaptic terminals

presynaptic

neurotransmitters are released here

repolarization

Na+ channels close, K+ channels open

neuroplasticity structural benefits

physical changes including growth of new neurons and/or dendritic modeling

neuroplasticity nureotransmitters

physical adjustments, can go from electrical to chemical synapses and vice versa

electrical synapses pros and cons

pros:

• high-speed transmission

• direct current flow from neuron

con:

• signal weakens transmitted to next cell

chemical synapses pros and cons

pros:

• amplification of post-synaptic neuron responses

• communication is modifiable “synaptic plasticity”

con:

• slower than direct electrical passage

triggering of neuropeptide release

depolarization opens calcium channels → calcium binds protein synaptotagmin → activation of complex fusion cell membranes

results in exocytosis/recycling and release from synaptic terminals

small-molecule neurotransmitters

amino acids and/or their derivative, synthesized in axon terminal, packaged into synaptic vesicles by transport molecules

neuropeptide neurotransmitters

short chains of amino acids, produced & released by neurons that act as chemical messengers

• synthesized as larger molecule

• carried to vesicles

• requires high action potentials & broken peptidase

long-term potentiation

After stimulation, long-lasting enhancement of synaptic transmission. Axon projections are stimulated, resulting in amplified and prolonged response to electrical stimulation

mechanoreception

response to mechanic stimulus

chemioreception

response to chemical stimulus

photoreception

response to light

salty/sour taste cells

include ionotropic receptors

sweet/bitter/umami cells

cells including metabotropic receptors

light interaction with photopigment receptors?

GCPRs specialized receptors with chromophore used to absorb light inducing conformational change within opsin (retinals)

Rods

response to dim light using rhodopsin as opsin in the receptor

• discs are non-continuous

• no outer membrane

• cyclic GMP (cGMP) usage

Cones

respond to bright light using 2+ opsin types

• connected by modified cilium

  • membrane with photopigments in flattened disks

Central Nervous System (CNS)

integrative controller - primarily the brain & spinal cord

Peripheral Nervous System (PNS)

connection to the rest of the body to the CNS

• autonomic (sympathetic & parasympathetic)

• somatic (sensory & motor)

Sensory Somatic Nervous System

communication through spinal nerves to areas below the neck

• project from dorsal root ganglion (DRG) of spinal cord to skin

• sensory nerve endings for mechanosensory input

Motor Somatic Nervous System

somatic neurons directly innervate muscle cells and communicate via acetylcholine s a neurotransmitter that

what is a nerve made of?

axons of multiple neurons in PNS bundle together

dendrite → soma → axon → node of Ranvier

Grey matter

cell bodies & synapses

white matter

tracts of myelinated axons wrapped around oligodendrocytes = many lipids & fats

Somatic Nervous System

response to sensory system

coordination of skeletal muscles/motor control

Parasympathetic Autonomic System

response to calming system

balances sympathetic sytems

Enteric Autonomic System

gut mobility - gut nerves communicated to brain via vagus nerve

Vagus Nerve

responsible for 90% of connections from the gut to the brain

composition influences brain/behavior

Somatic Nervous System

signals projected from dorsal root ganglion of spinal cord to the skin

• sensory nerve endings with specialized endings for mechanosensory

• cranial nerves in the head and neck

• motor control, direct innervated muscle cells

  • communicate via acetylcholine

Sympathetic Somatic Nervous System

two neuron communication

• short preganglionic neuron

• longer postganglionic

Parasympathetic Somatic Nervous System

two neuron communications

• long preganglionic neuron

• short postganglionic inside the target organ

Cerebrum

high sensory and motor functions, learning, memory, & emotions

cerebellum

motor coordination

medulla oblongata

autonomic and respiratory control

olfactory bulb

receives neural input about smells from nasal cavity