Bio Test 6

Spinal cord — conduction

Relays information through white-matter tracts; sensory goes up, motor goes down.

Ascending tracts

Carry sensory information upward through the spinal cord.

Descending tracts

Carry motor information downward through the spinal cord.

Decussation

Crossing of many neurons to the opposite side of the nervous system.

Spinal cord — reflex activity

The spinal cord controls reflex activity.

Central pattern generators (CPGs)

Neural circuits producing rhythmic outputs without rhythmic input.

CPG example

Locomotion, such as walking, swimming, or flying.

Meninges

Three protective layers: dura mater, arachnoid, and pia mater.

Blood-brain barrier

Protects the CNS from harmful substances such as bacteria and toxins.

Medulla oblongata

Controls heart activity, breathing rate, and blood pressure.

Pons

Involved in sleep and breathing.

Cerebellum

Coordinates movement and learned motor skills.

Midbrain

Coordinates muscles related to vision and hearing.

Thalamus

Gateway to the cerebral cortex; sensory information passes through it.

Hypothalamus

Helps regulate homeostasis, hunger, thirst, temperature, pituitary control, and autonomic functions.

Frontal lobe

Motivation, planning, mood, decisions, motor initiation, and gustation.

Parietal lobe

Integrates sensory information such as touch, pressure, pain, and joint position.

Temporal lobe

Hearing, learning, memory, emotions, smell, and language comprehension.

Occipital lobe

Vision.

Primary motor cortex

Located in the posterior frontal lobe; displays somatotopy.

Primary somatic sensory area

Located in the anterior parietal lobe; processes touch and displays somatotopy.

Association areas

Identify information and use memories to interpret it.

Cerebral lateralization

Different functions are more dominant in the brain's left or right hemisphere.

Right hemisphere

Associated with imagination, creativity, and artistic functions; controls the left body side.

Left hemisphere

Associated with analytical thinking, language, and reasoning; controls the right body side.

Reticular activating system (RAS)

Regulates arousal and sleep-wake transitions; becomes less active during sleep.

EEG

Records electrical activity and brain waves.

Stage 1 sleep

Small brain waves.

Stage 2 sleep

Skeletal muscles relax; sleep spindles appear.

Stage 3 sleep

Heart and breathing slow; slow-wave sleep occurs.

Stage 4 sleep

Hard to awaken; slowest heart and breathing rates and decreased body temperature.

REM sleep

EEG resembles wakefulness; muscles are inhibited; much dreaming occurs.

REM and memory

REM sleep is necessary for incorporating memories.

Hippocampus

Involved in learning and memory; converts new information into long-term memories.

Amygdala

Involved in emotions, memory, empathy, and fear responses.

Short-term memory

Working memory containing information from the previous few hours; about 7 bits of information.

Long-term memory

Information retained from previous days to years.

Factual memory

Memory processed through the hippocampus.

Procedural memory

Memory involving skills; associated with the cerebellum and motor areas.

Alzheimer's disease

Involves memory loss, hippocampal atrophy, tangles, amyloid plaques, and decreased acetylcholine.

Neurofibrillary tangles

Tangles found inside neurons; associated with Alzheimer's disease.

Amyloid plaques

Plaques found between neurons; associated with Alzheimer's disease.

Concussion

Brain is jarred against the cranium, disrupting neuronal electrical activity.

Meningitis

Inflammation of the meninges; can be viral or bacterial.

Rabies

Viral disease that travels through sensory neurons to the CNS and kills cells.

Epilepsy

Recurring episodes of abnormal electrical activity in the brain.

Parkinson's disease

Loss of dopamine-producing neurons causing tremors and impaired coordinated movement.

L-dopa

Treatment for Parkinson's that converts to dopamine in the brain.

Deep brain stimulation

A treatment involving stimulation of specific brain areas.

PET scan

Uses radioactive glucose to show areas of brain metabolism and activity.

MRI

Uses magnets and atomic responses to produce detailed brain images; no X-rays.

Functional MRI (fMRI)

Shows brain function by detecting oxygen-rich blood; greater visibility indicates greater activity.

MRI vs. fMRI

MRI studies brain anatomy; fMRI studies brain function.

Endocrine system

Endocrine glands secrete hormones into the blood.

Pineal gland

Produces a hormone; know its hormone and function.

Hypothalamus

Produces ADH, oxytocin, and releasing/inhibiting hormones affecting the pituitary.

ADH

Causes the kidneys to retain water.

Oxytocin

Causes uterine contractions and milk release from mammary glands.

Pituitary gland

Has anterior and posterior lobes; anterior produces 7 hormones, posterior stores ADH and oxytocin.

Anterior pituitary (adenohypophysis)

Produces 7 hormones, including growth hormone.

Posterior pituitary (neurohypophysis)

Stores ADH and oxytocin; contains axons projecting from the hypothalamus.

Thyroid gland

Contains follicles with colloid where thyroid hormones are stored; C cells produce calcitonin.

Thyroid follicle

Contains follicular cells and colloid where thyroid hormones are stored.

Parafollicular cells (C cells)

Produce calcitonin.

Calcitonin

Produced by parafollicular (C) cells of the thyroid gland.

Parathyroid glands

Four glands that produce parathyroid hormone (PTH).

Parathyroid hormone (PTH)

Produced by the parathyroid glands; know its function.

Thymus gland

Atrophies during adulthood; hormones influence T lymphocyte maturation.

Adrenal glands

Have an outer cortex and inner medulla that produce different hormones.

Adrenal cortex

Produces cortisol, testosterone, and estrogen.

Cortisol

Produced by the adrenal cortex; associated with chronic stress.

Adrenal medulla

Produces epinephrine and norepinephrine.

Epinephrine and norepinephrine

Produced by the adrenal medulla; sympathetic stimulation causes their release.

Pancreatic islets

Produce insulin and glucagon.

Insulin

Causes cells to take up glucose from the blood, regulating blood glucose.

Glucagon

Causes the liver to release glucose into the blood between meals.

Insulin vs. glucagon

Both regulate blood glucose; insulin promotes uptake, glucagon promotes release.

Pancreas — exocrine function

Produces digestive enzymes added to the small intestine to aid digestion.

Testes

Produce testosterone.

Ovaries

Produce estrogens and progesterone.

Other endocrine organs

Include the kidneys, stomach, small intestine, and others.