Neurons and Neuroglia in the Nervous System

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Questions and Answers

What is a characteristic of multipolar neurons?

Having no dendrites and a single axon

Having multiple axons and a single dendrite

Having a single axon and multiple dendrites (correct)

Having no axon and multiple dendrites

What is the function of oligodendrocytes in the CNS?

Producing CSF

Forming the blood-brain barrier

Seeking out and fighting pathogens

Forming myelin (correct)

What is the function of efferent neurons?

Forming the blood-brain barrier

Carrying impulses from sensory receptors to the CNS

Carrying impulses away from the CNS to effectors (correct)

Producing CSF

What is the function of the medulla oblongata?

Regulating heart rate and respiratory rate Signup and view all the answers

What is the function of the reticular formation?

Facilitating arousal and sleep-wake cycles Signup and view all the answers

What is a function of CSF?

Facilitating chemical stability Signup and view all the answers

What type of neuron has a single process extending from the cell body that divides into two branches?

Unipolar neuron Signup and view all the answers

What is the function of Schwann cells in the PNS?

Forming myelin Signup and view all the answers

What is the term for the enlargement of the spleen caused by various pathological conditions?

Splenomegaly Signup and view all the answers

Which of the following is NOT an example of an autoimmune disorder?

Kaposi sarcoma Signup and view all the answers

What is the term for when one molecule is mistakenly identified as another molecule due to their similar structure?

Mimicry Signup and view all the answers

What is the purpose of enzymes in digestion?

To break down complex food molecules into smaller nutrient molecules Signup and view all the answers

What causes the pyloric sphincter to open?

The contents of the stomach reaching a specific volume Signup and view all the answers

What is the function of lysozymes in saliva?

To defend against bacteria entering the body Signup and view all the answers

Which sphincter is controlled by the autonomic nervous system?

Cardiac sphincter/Lower esophageal Signup and view all the answers

What is the function of the cardiac sphincter/Lower esophageal?

To prevent stomach contents from flowing back up into the esophagus Signup and view all the answers

Which of the following is NOT a function of the kidneys?

Production of bile Signup and view all the answers

What is the effect of aging on the urinary system?

Decreased size of the kidneys and number of nephrons Signup and view all the answers

What is the function of ADH?

To increase water reabsorption Signup and view all the answers

What is hepatitis?

A viral infection of the liver Signup and view all the answers

What is the effect of aldosterone on urine production?

It increases water reabsorption Signup and view all the answers

What is the function of the urinary system?

To maintain fluid and electrolyte balance Signup and view all the answers

What is the function of the internal urinary sphincter?

To regulate the flow of urine out of the bladder Signup and view all the answers

What is respiratory acidosis caused by?

The system being unable to eliminate sufficient CO2 Signup and view all the answers

What is the purpose of secretion in the renal tubule?

To maintain the acid-base balance by secreting hydrogen ions Signup and view all the answers

What is the normal range of pH in the blood?

7.35-7.45 Signup and view all the answers

What is the function of the glomerular capsule?

To filter out waste products from the blood Signup and view all the answers

What is reabsorption in the renal tubule?

The process of moving materials from the tubules back into the bloodstream Signup and view all the answers

What is metabolic alkalosis caused by?

The loss of acid usually due to excessive vomiting Signup and view all the answers

What is the trigone?

The triangular area of the bladder floor defined by the openings to the ureters and urethra Signup and view all the answers

What is the function of secretin in the digestive system?

To release bicarbonate ions to neutralize acidic chyme in the duodenum Signup and view all the answers

What is the purpose of the rugae in the lining of the stomach?

To provide a larger surface area for gastric pits and glands Signup and view all the answers

What is the function of the pyloric sphincter?

To regulate the movement of food from the stomach into the small intestine Signup and view all the answers

What is the main function of the small intestine?

To absorb nutrients into the bloodstream Signup and view all the answers

What is the role of cholecystokinin in the digestive system?

To stimulate the release of bile into the duodenum Signup and view all the answers

What is the function of segmentation in the small intestine?

To ensure all contents of the small intestine come in contact with villi for absorption Signup and view all the answers

What is the function of the ileocecal valve?

To control the movement of materials from the small intestine into the colon Signup and view all the answers

What is the term for the partially digested food in the stomach?

Chyme Signup and view all the answers

Study Notes

Neurons

Multipolar neurons have several dendrites and a single axon, and their cell bodies are located in the brain and spinal cord
Bipolar neurons have one dendrite and one axon
Unipolar neurons have a single process extending from the cell body that divides into two branches extending in opposite directions, functioning as a single axon, and are sensory neurons from the skin and organs

Neuroglia

In the CNS:
- Astrocytes form the blood-brain barrier
- Oligodendrocytes form myelin
- Ependymal cells produce CSF
- Microglia seek out and fight pathogens
In the PNS:
- Schwann cells form myelin
- Satellite cells control the environment for ganglia

Nerve Divisions

Afferent (sensory division): carries impulses from sensory receptors to the CNS
Efferent (motor division):
- Carries impulses away from the CNS to effectors
- Has two subdivisions:
  - Somatic: voluntary control of skeletal muscle
  - Autonomic: involuntary control of cardiac muscle, smooth muscle, and glands

Brainstem

Has four parts:
1. Medulla oblongata:
  - Ascending (sensory) and descending (motor) information passes through
  - Contains centers to regulate heart rate, respiratory rate, and blood vessel diameter
  - Contains the emetic center
2. Pons:
  - Serves as a bridge for motor tracts to the cerebellum
3. Midbrain:
  - Has four bulges called colliculi on its posterior surface
  - Two superior colliculi are important for visual reflexes
  - Two inferior colliculi are important for auditory reflexes
4. Reticular formation:
  - A group of cell bodies called nuclei in the CNS and ganglia in the PNS
  - Important for arousal and responsible for sleep-wake cycles

CSF and Immune System

Functions of CSF:
1. Provides buoyancy
2. Provides protection
3. Facilitates chemical stability
Autoimmune disorders: result of the immune system attacking self-antigens, including rheumatoid arthritis, Graves' disease, and myasthenia gravis
Immunodeficiency disorders:
- Congenital: from birth
- Acquired: AIDS (final stage of HIV), which can cause Kaposi sarcoma and affect the ability to fight opportunistic infections

Digestive System

Mechanical digestion: physical breakdown of food into smaller pieces
Chemical digestion: splitting of complex, non-absorbable food molecules into small, absorbable nutrient molecules by hydrolysis
Enzymes that speed up the reaction and enable digestion to occur
Functions of the digestive system:
1. Ingestion
2. Digestion
3. Absorption
4. Defecation

Small Intestine

Has three parts: duodenum, jejunum, and ileum
All parts have smooth muscle in their walls and are lined by villi
Endocrine cells of the duodenum secrete secretin and cholecystokinin
The ileocecal valve controls movement of materials from the small intestine to the colon

Stomach

Has three layers of smooth muscle in its walls, oriented in different directions
The lining of the stomach has rugae for more surface area to accommodate gastric pits that lead to gastric glands

Hormones and Digestion

Secretin: tells the pancreas to release bicarbonate ions to neutralize the chyme in the duodenum
Cholecystokinin: secreted by endocrine cells in the duodenum in response to the presence of lipids
Chyme: the mixture of gastric secretions and bolus after digestion in the stomach
Segmentation: ensures all contents of the small intestine come into contact with villi for absorption
Peristalsis: a series of involuntary muscle contractions that moves the bolus through the esophagus

Colon and Rectum

Regions of the colon:
1. Cecum
2. Ascending colon
3. Transverse colon
4. Descending colon
5. Sigmoid colon
6. Rectum
Sphincters:
1. Pyloric sphincter
2. Hepatopancreatic sphincter
3. Internal anal sphincter
4. External anal sphincter
5. Cardiac sphincter/Lower esophageal sphincter

Urinary System

Functions of the kidneys and urinary system:
- Kidneys:
  1. Excretion of wastes through urine
  2. Regulation of blood volume
  3. Delivery of urine from the body
  4. Control of urine production
- Urinary system:
  1. Removal of metabolic wastes
  2. Maintenance of body fluid and electrolyte balance
  3. Maintenance of body acid-base balance
  4. Regulation of blood pressure
Hormones that regulate urine volume:
1. ADH (antidiuretic hormone): controls water reabsorption
2. Aldosterone: regulates sodium ion reabsorption in the distal convoluted tubule
Effects of aging on the urinary system:
1. Size of the kidneys and the number of nephrons decrease
2. Glomerular filtration rate and reserve capacity decrease
3. Drugs are cleared less efficiently
4. Responsiveness to ADH is decreased
5. 80% of elderly men experience benign prostatic hyperplasia, which makes micturition difficult
6. Elderly women often experience incontinence due to weakened pelvic floor muscles

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Description

This quiz covers the structure and function of neurons, including multipolar, bipolar, and unipolar neurons, as well as the role of neuroglia in the central nervous system.