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Lent Term lectures

Reproduction: Prof. Bill Colledge (6 lectures)

This lecture series on reproduction will focus primarily on sexual reproduction in mammals. However, there will be a comparative approach to topics which include sexual differentiation, gametogenesis and the control of reproductive function. The lectures will emphasise the important role of hormones in the onset and maintenance of normal reproductive function and fertility.

Lecture 1: Sexual differentiation
This lecture will introduce the principles of sexual and asexual reproduction, and will outline the advantages and disadvantages of each method of procreation. Concentrating on sexual reproduction, it will discuss the development of the gonads and reproductive tracts in male and female animals. In addition, the lecture will examine the control of sexual differentiation by genetic and hormonal factors, with reference to abnormalities in sexual development.

Lecture 2: Spermatogenesis
This lecture will focus on the process of spermatogenesis, and will emphasise identification of the spermatogenic cell types and the physiological significance of each stage. The mechanisms used to ensure the continuous production of many sperm will be discussed. The lecture will examine the control of testicular function and the importance of the blood-testis barrier.

Lecture 3: Sperm maturation and fertilisation
This lecture will describe the transport and maturation of sperm on the journey through the male and female reproductive tracts. It will highlight the obstacles to fertilisation and the importance of the composition of the seminal fluid. The process of fertilisation and the mechanisms t prevent polyspermy will be discussed.

Lecture 4: Oogenesis and ovulation
This lecture will focus on the process of oogenesis and the development of ovarian follicles and the corpus luteum. The control of ovarian function, including oogenesis, ovulation and luteolysis, will be examined. An overall comparison of gametogenesis in male and female animals will be made.

Lecture 5: Oestrous and menstrual cycles
This lecture will describe the cyclic changes in reproductive hormones in non-pregnant female animals, and will highlight the effects of these hormones on the reproductive tract. The control of the onset of puberty and the manipulation of reproductive cycles will be discussed.

Lecture 6: Fertility
This lecture will examine the various environmental and physiological influences on fertility. It will discuss the importance of spacing pregnancies and the approaches used by different animal species. The lecture will explore the role of the pineal gland in seasonal breeding.

Early Pregnancy: Dr Erica Watson (2 lectures)

The two lectures on early pregnancy will concentrate on the changes occurring in about the first week. The first lecture will focus on the changes in the embryo and the second on interactions between embryo and mother.

Lecture 1: Embryogenesis
This lecture will describe the sequence of events during which the a single cell (the egg), expressing largely the maternal genome, forms a small number of identical cells, expressing the embryonic genome, and finally forms differentiated embryonic an extra-embryonic cells. The movement of the egg through the oviduct and into the uterus during this development will also be described.

Lecture 2: Maternal recognition of pregnancy
In order for the pregnancy to be maintained normal female cycling has to be stopped very soon after fertilisation (to prevent luteolysis and hence the subsequent fall in progesterone levels). Methods by which the corpus luteum is maintained will be discussed by reference to a number of different species.

Placental Function: Dr David Bainbridge (1 lecture)

How we define a 'placenta' and how the placenta relates to the fetal membranes. Functions of the placenta – exchange of nutrients, gases and wastes; protection; immunological integrity; hormone secretion. Evolution and development of the fetal membranes and how they connect to the embryo.

Pregnancy and the Fetus: Dr Wendi Bacon (4 lectures)

Lactation: Dr David Bainbridge (1 lecture)

The evolution and relevance of lactation in mammals. The microscopic structure of the mammary gland. The constituents of milk and how they can vary between species. The physiological processes underlying mammogenesis, lactogenesis, galactopoiesis, milk ejection, mammary involution and lactational anoestrus. The energetic costs of lactation and how different mammalian taxa have evolved to exploit lactation.

The Neonate: Dr Emily Camm (1 lecture) 

This lecture will consider the changes that occur to the respiratory and circulatory systems, as well as fuel reserves and digestion, in the newborn. Changes in these systems, and how the neonate copes with them, will be discussed. The additional problems faced by the prematurely delivered newborn will be also considered.

Digestion & Absorption: Dr Matt Mason (7 lectures)

This lecture course recapitulates some of the topics covered in IA Physiology of Organisms, but we shall go into much more detail! The first six lectures will focus on human physiology, including brief synopses of the clinical implications of gastrointestinal physiology as well as a look at the history of this fascinating area. In the last lecture we shall consider digestive physiology in other mammals from comparative and zoological perspectives, building on what you may already know from IA.

Lecture 1: The Basics; Salivation
A general overview of the anatomical organisation of the gastrointestinal tract, together with an idea of the mechanisms of control. Endocrine, paracrine and neurocrine transmitters are considered. In the last part of the lecture, we shall review the mechanism and control of salivation.

Lecture 2: Mostly Motility
Continuing our look at 'the basics', we shall review the physiology of gastrointestinal smooth muscle, its electrical activity and its role in the motility of the digestive tract. We shall look at some of the reflexes, both intrinsic and extrinsic, involved in co-ordinating gastrointestinal motility. Then we can begin to consider the activities of the digestive system – today we shall consider the trip from mouth to stomach, and back again.

Lecture 3: The Stomach
Considering the physiology of the stomach. The lecture will concentrate first on gastric motility and then on acid secretion. We will cover the roles of reflexes in acid secretion and in the control of stomach emptying. The formation and treatment of gastric ulcers will be considered.

Lecture 4: The Small Intestine
Looking at the physiology of the small intestine and its role in digestion. We shall first consider the motility of the small intestine, and then the nature and control of the exocrine secretions that drain into it. We shall look at the chemical digestion and absorption of the major food substances.

Lecture 5: Water, Electrolytes and the Large Intestine
We shall consider the absorption of fluid and electrolytes in the small and large intestines, before turning our attention fully to the physiology of the latter. We shall study motility of the large intestine, including the mechanisms of defaecation. We shall then consider the significance of the gut flora and the composition of flatus and faeces.

Lecture 6: Transport and Storage
We shall examine the fate of the nutrients absorbed from the digestive system. We shall be looking at the physiological roles of the liver and endocrine pancreas, and the mechanisms for maintaining stable blood glucose levels before and after a meal.

Lecture 7: Comparative Digestive Physiology
We shall consider digestive physiology in mammals other than humans, specifically those which have particular adaptations towards the digestion of cellulose by microbial fermentation. We shall explore the advantages and disadvantages of foregut and hindgut fermentation strategies, and then consider the limited cellulose digestion in the human digestive tract.

Weight Regulation & Nutrition: Dr Matt Mason (2 lectures)

Lecture 1: Metabolism, and responses to fasting
In the first lecture, we shall examine the concepts o metabolic rate and respiratory quotient, and we shall examine ways in which body fat levels can be measured. We will then consider the endocrine response to fasting, both in early stages (i.e. overnight), and over the course of day or weeks. We will then consider the effects of protein-energy malnutrition, of great importance in Third World countries.

Lecture 2: Control of food intake, and obesity
In the second lecture, we will examine the neuroendocrine control of food intake. A consideration of classical lesion and parabiosis studies will lead us right up to modern concepts of hypothalamic control of appetite. We will also consider how dysfunctions in various parts of this system can lead to obesity, and how this might be treated in theory and in practice.