Mammalogy Topic 7 Control Systems and Biological Rhythms

CNS (central nervous system)

Develops from dorsal hollow nerve, contains all the interneurons and most perikarya, may constrain sensory and motor neurons

PNS (peripheral nervous system)

Contains only sensory and motor neurons, divided into sensory (afferent) and motor (efferent) subdivisions

Spinal cord

Connects PNS and brain, located in vertebral canal, where reflexes occur, begins at medulla oblongota

Spinal nerves

Allow for communication between the cord and the rest of the body, enter and exit vertebral canal by intervertebral foramina, regular segmented pattern across the spinal cord,

Conus medullaris

Tapering end of the spinal cord

Cauda Equina

Numerous spinal nerves arising from conus medullaris

Medulla oblongota

End portion, part of the brain stem, contains perikarya (cell bodies of neurons) for cranial nerves

Cerebellum/Pons

Responsible for gracefulness and coordination of somatic motor activities, contains perikarya

Midbrain

Contains perikarya of cranial nerves

Reticular formation

Responsible for rigid automatically controlled behavior, made up of the cerebellum/pons, midbrain and medulla oblongota

Thalamus

Main relay center between cerebrum and CNS

Epithalamus

Dorsal to the thalamus and contain endocrine organ called pineal gland

Hypothalamus

Controls ANS, body temperature, hunger, thirst, circadian rhythm, and control of the endocrine system

Diencephalon

Part of the forebrain, is comprised of thalamus/epithalamus/hypothalamus

Cerebrum

Greatest degree of variation between mammalian orders and families, contains cerebral cortex and white matter

Cerebral white matter

Contains axons traveling to and from neocortex, contains basal nuclei (clusters of cerebral cortex) - amygdala

Neo/cerebral cortex

Lots of neurons associated with memory banks, somatotrophy (growth)

Rods

Use dim light, achromatic vision

Visual Streak

Animals inhabiting a flat visual field have regions of cines that form linearly

Fovea

Cone dense regions, color vision

Cones

Uses bright light, provides resolution,

Photoreceptors

Specialized neurons of retina that respond to specific wavelengths

Tapetum Lucideum

Structure composed of guanine crystals that reflect light, "eye shine" in nocturnal species

Cornea

First stage of light passing, refracts and bends light

Lens

Focuses the light on the retina, the amount of light is controlled by the iris

Echolocation

Whales, bats, shrews, and some blind mammals

Cochlea

Spiral shaped portion where sound waves are converted to nerve signals

Cochlear duct

Organ of corti, ultrasound, infrasound, Mesozoic adaptation

Middle ear

Receives sound waves from tympanic membrane by means of auditory ossicles, malleus- incus- stapes

Tympanic membrane

Thin membrane that divides the outer and middle ear and changes sound waves into vibrations; also known as the eardrum, connects to the external auditory canal

Pinna

Serves to capture and concentrate sound waves, connects to the external auditory canal

Olfactory mucosa

Solution that receives chemical stimulus, more than 1000 receptor proteins

Olfaction

Chemoreceptive sense, finding food, indentifying conspecifics, avoiding predators, indentifying territories and social status

Limbic system

Connects nose and brain, elicits strong memories and reactions

Vomeronasal organ

Detects pheromones, evagination in nasal cavity during development

Pituitary gland

Controls hormone activity, controlled by the hypothalamus,

Anterior pituitary

Produces, somatotrophin, thyrotrophin, adrenocorticotropin, gonadotropin, prolactin, melanocyte stimulating hormone

Posterior pituitary

Produces ADH and oxytocin

Adrenal medulla

Central portion of adrenal gland, sympathetic nervous system in emergencies

Adrenal cortex

Outer portion of adrenal gland, produces hydrocortisone

Gonads

Testes/ovaries

Thyroid

Produces calcitonin and thyroxine (metabolic hormones)

Parathyroids

Produce PTH an antagonist of calcitonin

Circadian rhythms

Any biological process that endogenous, entrainable, and lasts 24 hours

Noncircadian rhythms

Ultradian, infradian, circalunal, circannual