BIOL125 Lecture Notes - Lecture 2: Thyroid, Gastrin, Adrenal Cortex

24 views5 pages

jadeoyster197

27 Jun 2018

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

WEEK 4 LC  TEST

BIOL LC  Cell-to-cell communication

The human body

- The number of cells in the human body

o37 trillion (3.7 x 1013)

- Cells communicate and sense  how homeostasis is controlled

- Ability to respond to external and internal stimuli

- Many of the organisms are negatively controlled  negative feedback

Control systems in the body  neuroendocrine system

- Nervous system  brain and spinal cord  communicates with rest of body

- Endocrine system  plays important role  secretes hormones that act as primary

messengers  released into ECF where it goes into blood and travels around

circulatory system, affecting cells with specific receptors

- Hypothalamo-hypophyseal system  hypothalamus is an overlap between nervous

and endocrine system  associated with pituary gland  hypothalamus is a

neuroendocrine organ

oHypothalamus secretes some hormones – controls secretion of

(interior/anterior?) lobe hormones

oPortal system allows fast communication between neuroendocrine glands

- Neuroendocrine system 

Cell-to-cell communication

1. Juxtacrine (direct) communication

oAka. Contact-dependent signalling

oCells need to be in physical contact with each other through signalling

membrane proteins

Via gap junctions (eg: cardiac muscle)

Via “Notch pathway” (essential during embryonic development)

oEg: Coordination of cilia in epithelial cells

2. Indirect communication

Juxtacrine (direct) communication:

Gap junctions

- Water-filled pores

- Allow rapid flow of ions (eg: calcium ions)

- Comprised of

o2 connexons

o6 connexin subunits/connexon

- Allows the passage of anything up to 1 kDa (kilodalton – unit of size for proteins)

(small) between adjacent and contacting cells

oEg: ions, glucose, amino acids  whatever small substances the cells have to

share with one another

oMacromolecules cannot pass through

- Gap junctions located in

oHeart

oSmooth muscle tissue (visceral)  calcium is needed for contraction of muslce

oNeurons = Electrical synapse

Allow rapid spread of action potentials

find more resources at oneclass.com

Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in

Indirect communication (cells are not in direct contact)

- No direct contact between communicating

cells

- Requires specific messenger molecules

oEndocrine

oParacrine

o(autocrine)

oNeurocrine

oNeurotransmission

Endocrine signalling

- Messenger molecule = hormone

oControl over a distance

oChemical released from endocrine cell is secreted by exocytosis, diffuses into

ECF, goes into capillary to travel around circulatory system

oWherever there are receptors, they are called target cells

oProduced by an endocrine gland

oReaches target cells via bloodstream  may travel long distances

Thyroid gland (thyroxine, calcitonin)  important in calcium regulation

Adrenal cortex (cortisol, aldosterone)

Cortisol  important in sugar level control  when glucose

levels are not sufficient, fats and proteins can be used

Aldosterone  targets kidney to restore sodium back into the

blood and cause water re-absorption

Testes (testosterone)

Paracrine signalling

- Messenger molecule is called paracrine hormone

oIn mature cells, paracrine signalling is important in blood clotting, tissue

repair, formation of tissue

oProduced by a paracrine gland

oDoes not enter bloodstream

oRemains in the interstitial fluid  acts on nearby target cells

Paracrine hormones in the gastrointestinal system (eg: G cells 

gastrin)

Eg: secretion of growth factors

Autocrine signalling

- For the cell to carry out a response, it needs to be stimulated  self-stimulated

- Local hormone doesn’t need to enter the bloodstream

- Messenger molecule is called autocrine hormone

oProduced by an autocrine cell

oDoes not enter bloodstream

oRemains in the interstitial fluid  acts on the same cell that produced it

T lymphocyte growth factor  important for specific immune response

Progesterone (intracrine effect)

Neurotransmission

find more resources at oneclass.com

Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in

Document Summary

The number of cells in the human body: 37 trillion (3. 7 x 1013) Cells communicate and sense how homeostasis is controlled. Ability to respond to external and internal stimuli. Many of the organisms are negatively controlled negative feedback. Control systems in the body neuroendocrine system. Nervous system brain and spinal cord communicates with rest of body. Endocrine system plays important role secretes hormones that act as primary messengers released into ecf where it goes into blood and travels around circulatory system, affecting cells with specific receptors. Contact-dependent signalling: cells need to be in physical contact with each other through signalling membrane proteins. Via notch pathway (essential during embryonic development: eg: coordination of cilia in epithelial cells. Allow rapid flow of ions (eg: calcium ions) Comprised of: 2 connexons, 6 connexin subunits/connexon. Gap junctions located in: heart, smooth muscle tissue (visceral) calcium is needed for contraction of muslce, neurons = electrical synapse. Indirect communication (cells are not in direct contact)

Related Questions

1. Kidneys help to maintain a proper balance of _________ within the body.

Phosphorous

Chloride

Potassium

Calcium Phosphate

ions

All of the above

2. The nervous system has how many major categories?

3. Which major category of the nervous system contains both the Somatic and the Autonomic divisions?

Central Nervous System

Peripheral Nervous System

Neither of these

Both of these

4. Which organ or structure helps to control the master endocrine gland (pituitary gland)?

The pancreas

The thorax

Peyerâs patches

The hypothalamus

6. This tiny gland is located at the base of the brain and produces the hormone melanin.

Parathyroid

Pituitary

Hypothalamus

Pineal

7. These glands are situated right above the kidneys. The hormones produced by these glands help us to cope with stress.

Thyroid

Parathyroid

Hypothalamus

Adrenals

8. The hormones necessary for the production of sperm are produced in the __________.

Kidneys

Testes

Ovaries

None of the above

9. The bloodstream assists the endocrine organs and structures by:

Removing hormones from the body

Delivering hormones to target cells

Delivering hormones to secretory cells

The bloodstream does not come into contact with endocrine structures or organs
10. The pancreas _____________.

Is a master gland that controls many other glands

Produces progesterone and oestrogen

Is a salivary gland

Regulates blood sugar, aid in digestion

11. The basic function of the endocrine system is ________ in nature.

Digestive

Reproductive

Hormonal

Proximal

13. Urinary tract infections (UTIs) are experienced by many people during their lifetimes. Urinary tract infections can involve any bacterial infection of the urinary system structures; the kidneys, bladder, ureters, or urethra. They are caused by bacteria entering the body through the urethra and traveling upward into the body. Symptoms can range from mild discomfort when urinating to extreme pain and the loss of blood during urination. They occur more frequently in women than men, and are often treated by antibiotics in addition to home remedies, such as drinking more water and drinking cranberry juice.

Based on what you have learned about the cause of urinary tract infections, which of the following precautions would help to prevent reoccurring infections?

Taking pain medication when symptoms occur

Placing a hot pack on the abdomen when symptoms occur

Practicing good hygiene Exercising regularly

14. The nervous system is divided into two major divisions: the Central Nervous System and the Peripheral Nervous System. Those divisions have structures that can be classified as belonging to two different subdivisions: the Somatic and the Autonomic systems. The nervous system can be summarized as a complex system of interconnected nerves and special cells called neurons that are used to transmit information (by means of small electrical impulses). Use the information in the table below to help answer questions about the nervous system. Division Organs & Structures Functions Central Nervous System (CNS) Brain Spinal Cord Nerves This is the bodyâs assessment and communication center. It analyzes the information received from the sensory neurons and responds. Peripheral Nervous System (PNS) Sensory Neurons Ganglia (clusters of neurons) Nerves that connect to one another and to the CNS The sensory neurons react to physical stimuli such as light, sound, heat, and pressure, and transmit that information to the CNS. Subdivisions Description Examples Somatic The Somatic system is comprised of nerves that connect the brain and spinal cord to the muscles of the body and sensory receptors in the skin. Reactions to physical stimuli like heat or light. Using your hand to touch Eating food Autonomic The Autonomic system largely involuntary. This system controls the unconscious functions of the body. Breathing Blood Pressure

Feeling overwhelmed or startled by exposure to very loud noises is likely a reaction to information collected by which subdivision of the nervous system:

Somatic

Autonomic

No answer text provided.

15. The thyroid gland is perhaps the most well-known member of the pancreatic system. Many adults are screened for thyroid problems during routine physical exams. This butterfly shaped gland is found at the base of the neck and releases hormones that affect the bodyâs metabolism (the way the body uses energy). The thyroidâs two main hormones are T3 and T4, and they affect many body functions, including: â¢ Breathing â¢ Heart rate â¢ Central and peripheral nervous systems â¢ Body weight â¢ Muscle strength â¢ Menstrual cycles â¢ Body temperature â¢ Cholesterol levels Two common disorders associated with the thyroid include hyperthyroidism and hypothyroidism. Some of the symptoms associated with these disorders are listed in the table below. Hyperthyroidism (Too many hormones released) Hypothyroidism (Too few hormones released) Anxiety Irritability or moodiness Nervousness, hyperactivity Sweating or sensitivity to high temperatures Hand trembling (shaking) Hair loss Missed or light menstrual periods Trouble sleeping Tiredness and fatigue Difficulty concentrating Dry skin and hair Depression Sensitivity to cold temperature Frequent, heavy periods Joint and muscle pain A patient complains of arthritis-like pain in the joints of her hands, but tests for arthritis come back negative. The doctor then suggests a thyroid function test. The doctor is most likely concerned about:

High levels of T3 and T4 hormones in the body

Low levels of T3 and T4 hormones in the body

No answer text provided.

No answer text provided

rubymule151

BIOL125 Lecture Notes - Lecture 2: Thyroid, Gastrin, Adrenal Cortex

Document Summary

Get access

Related Documents

LSB258 Lecture Notes - Lecture 2: Insulin, Estrogen, Thymosin

Pharmacology 3620 Lecture Notes - Lecture 34: Alpha Cell, Centroacinar Cell, Pancreas

PSYCH 330 Study Guide - Midterm Guide: Monoamine Neurotransmitter, Prefrontal Cortex, Neuroendocrinology

Related Questions